At a bygone plantation in coastal Georgia, Joseph McGill Jr. creaks open a door to inspect his quarters for the night. He enters a cramped cell with an ancient fireplace and bare walls mortared with oyster shell. There is no furniture, electricity or plumbing.

“I was expecting a dirt floor, so this is nice,” McGill says, lying down to sample the hard pine planks. “Might get a decent sleep tonight.”

Some travelers dream of five-star hotels, others of visiting seven continents. McGill’s mission: to sleep in every former slave dwelling still standing in the United States. Tonight’s stay, in a cabin on Georgia’s Ossabaw Island, will be his 41st such lodging.

McGill is 52, with a desk job and family, and isn’t fond of sleeping rough. A descendant of slaves, he also recognizes that re-inhabiting places of bondage “seems strange and upsetting to some people.” But he embraces the discomfort, both physical and psychological, because he wants to save slave dwellings and the history they hold before it’s too late.

“Americans tend to focus on the ‘big house,’ the mansion and gardens, and neglect the buildings out back,” he says. “If we lose slave dwellings, it’s that much easier to forget the slaves themselves.”

A century ago, the whitewashed cabins of former slaves remained as ubiquitous a feature of the Southern landscape as Baptist churches or Confederate monuments. Many of these dwellings were still inhabited by the families of the four million African-Americans who had gained freedom in the Civil War. But as blacks migrated en masse from the South in the 20th century, former slave quarters—most of which were cheaply built from wood—quickly decayed or were torn down. Others were repurposed as toolsheds, garages or guest cottages. Of those that remain, many are now endangered by neglect, and by suburban and resort development in areas like the Georgia and Carolina Low Country, a lush region that once had the densest concentration of plantations and enslaved people in the South.

McGill has witnessed this transformation firsthand as a native South Carolinian who works for the National Trust for Historic Preservation in Charleston. But it wasn’t his day job that led him to sleep in endangered slave cabins. Rather, it was his weekends as a Civil War re-enactor, wearing the uniform of the 54th Massachusetts, the black unit featured in the movie Glory. Donning a period uniform and camping out, often at antebellum sites, “made the history come alive for me,” he says. Re-enacting the 54th has also drawn public attention to the pivotal role of black soldiers in the Civil War. So in 2010, when Magnolia Plantation near Charleston sought to publicize restoration of its neglected slave cabins, McGill proposed sleeping in one of them.

“I was a little spooked,” he says of his overnight stay. “I kept getting up hearing noises. It was just the wind blowing limbs against the cabin.” His simple bedroll, laid on the hard floor, also didn’t make for a comfortable night. But the sleepover succeeded in drawing media attention to the slave cabins, which have since been opened to the public. So McGill began compiling a list of other such structures and seeking out their owners, to ask if he could sleep in them.

He also tried to recruit members of his re-enacting unit to join him on his overnights. One of them, Terry James, says that at first, “I thought Joe had lost his mind. Why go stay in a falling-down slave cabin with snakes and insects?” But as James reflected on his ancestors, who not only survived slavery but also succeeded after the Civil War in buying and farming land that is still in his family, he decided he “needed to know more about what they endured and overcame.” So he accompanied McGill on a wretched August overnight in a cabin that had been boarded up for years and was infested with mold. “The air was so awful we slept with the door open,” James recalls. “It was hot and humid and buggy as heck.”

For their next overnight together, James chose to make the experience even more unpleasant. He showed up with antebellum wrist shackles he’d been lent by the owner of a slave relic museum and put them on before lying down for the night. “I wanted to honor the ancestors who came over in the middle passage,” James explains, “and to feel a little of what it was like to be bound.”

Now he knows. “It’s impossible to really get comfortable with your wrists shackled.” He woke repeatedly during the night and lay awake thinking about enslaved Africans packed into the bowels of ships. His constant jostling and the clank of his shackles kept McGill awake and haunted him, too. Even so, James has repeated the ritual at more than a dozen slave dwellings since. “It makes you realize how blessed you are that your ancestors survived and struggled so that eventually their children could have a better life,” he says. His overnights have also become a source of gentle teasing by his wife, who tells him, “You’d rather sleep in shackles in a slave cabin than sleep with me.”

James and his irons weren’t part of McGill’s recent weekend in Georgia, but it was a remarkable outing nonetheless. McGill’s destination, Ossabaw Island, can be reached only by boat from a dock ten miles south of Savannah. Ossabaw is the third largest of Georgia’s barrier islands and among its least developed. In fact, its principal inhabitants are 2,500 feral pigs, as well as alligators, horseshoe crabs and armadillos. Only four people live there full time, including a 100-year-old heiress from Michigan who enjoys reading Sherlock Holmes and Agatha Christie novels in her family’s mansion.

“I’m not sure if this is the Old South, the New South or the weird South,” McGill says, as he disembarks at a wharf and walks past palm trees and salt marsh to a well-shaded Victorian hunting lodge. “All I know is it’s very different from other places I’ve stayed.”

The island’s centenarian, Eleanor Torrey West, whose parents bought Ossabaw in 1924 as a Southern retreat, maintains life rights to her family’s house and grounds. The state now manages the island in association with the Ossabaw Foundation, which sponsors educational programs, including one scheduled in conjunction with McGill’s visit. Among the dozen people along for the trip is Hanif Haynes, whose forebears were among the hundreds of enslaved people on four plantations that once dotted Ossabaw. Many former slaves remained after the Civil War, as sharecroppers, before resettling on the mainland in the late 19th century, mostly in the community of Pin Point, the birthplace of Supreme Court Justice Clarence Thomas.

“We left the island, but held on to the traditions and language,” says Haynes, who switches easily into Geechee, the Creole tongue of the Georgia Sea Islands, where isolation and close ties to West Africa and the Caribbean created a distinctive and enduring culture (its cousin in South Carolina is known as Gullah). One mark of this coastal culture that remains is “haint blue,” an azure paint that slaves and their descendants applied to doorways and windowsills to ward off spirits. The practice is thought to derive from West African beliefs that water forms a divide between the spirit and human world.

“Haint blue” paint is still visible on the three surviving slave cabins at Ossabaw, which stand in a tidy row beside what was once a field of Sea Island cotton. The cabins’ building material is also distinctive. While most slave dwellings were made of wood, and less commonly, brick, those at Ossabaw are tabby: a concretelike mixture of oyster shell, lime, sand and water. Tabby was a cheap and convenient resource along the coast, and also durable, which helps explain why Ossabaw’s cabins have survived while many others have not.

Another reason the cabins endured is that they were occupied long after the Civil War and as recently as the 1980s by caretakers and cooks working on the island. The cabins are now being returned to their original appearance. Each one is 30 by 16 feet, divided into two living spaces by a large central chimney with an open fireplace on either side. Eight to ten people would have occupied each dwelling. This left little or no room for furniture, only pallets that could be laid on the floor at night.

“Cabins like this were basically used for sleeping, and cooking indoors when the weather was bad,” McGill explains. Otherwise, slaves who labored in the fields lived almost entirely outdoors, working from sunup to sundown, and cooking and doing other chores (as well as gathering to eat and socialize) in the yard in front of their adjoining cabins.

There were originally nine cabins on this “street,” or row of slave dwellings. Of the three that survive, only one had glass in the window frames and wood covering the dirt floor. This may indicate that its original occupant was the plantation’s “driver,” a slave foreman given small privileges for supervising other bondmen. This cabin has also undergone last-minute restoration in time for McGill’s visit, including the installation of yellow pine floorboards from the mid-19th century.

“When people know I’m coming they spruce the place up,” McGill says, unfurling his bedroll. He approves of this, since “it means they do preservation work that’s needed now, rather than putting it off.”

Ossabaw, a low-lying island ringed by tidal marsh, has swarms of gnats and mosquitoes, as well as chiggers. But this early summer night turns out to be uncharacteristically free of insects, apart from blinking fireflies. McGill is also reasonably comfortable, having brought a pillow and a cotton pad to put under his bedroll—while noting that slaves would have had only simple bedding stuffed with straw, corn husks or Spanish moss. In the dark, his thoughts are likewise focused on practical matters, rather than mystical communion with the enslaved who once slept here. He speculates, for instance, about the opportunity and challenge for slaves seeking to escape an island like Ossabaw rather than a mainland plantation. “I’ll need to research that,” he says, before drifting off to sleep, leaving me to toss and turn on the hard wood floor to the sound of his snores.

In the morning we awake to birdsong and sun streaming through the cabin’s open window. “It’s almost 7. We slept in,” McGill says, checking his watch. “The slaves who lived here would have been in the fields for more than an hour already.”

McGill often shares his experiences with school groups and other visitors to antebellum sites like Ossabaw. When doing so, he speaks plainly about the cruelties of slavery. But he strives to keep pain and outrage in check. “I’m not trying to provoke people to anger,” he says. His missions are preservation and education, and he needs the cooperation of the owners and stewards of former slave dwellings who might be put off by a more strident approach. He also feels blacks and whites need to talk openly about this history, rather than retreat into age-old division and distrust. “I want people to respect and restore these places, together, and not be afraid to tell their stories.”

This has happened in gratifying ways during a number of his stays. He tells of two sisters who had avoided any contact with the Virginia plantation where their ancestors were enslaved, despite invitations to visit. After overnighting with him at a slave cabin on the site, and realizing there was genuine interest in their family’s history, one of the women became a volunteer guide at the plantation. Local students, black and white, have joined McGill and written essays about how the experience changed their views of race and slavery. “Suddenly, what I read in textbooks became something I was able to see in my mind’s eye,” wrote one teenager in South Carolina.

McGill has also found that older white Southerners who own or operate properties with slave dwellings are much more receptive to his project than they might have been just a decade or two ago. In only a few instances have his requests to stay been rebuffed. More often he’s been enthusiastically welcomed, dined with his hosts and even been given the keys to the big house while the owners go off to work. “Sometimes I sense guilt is part of what’s driving people, but whatever it is, having me visit and acknowledge their preservation of these places makes them feel they’re doing the right thing,” he says. “It’s not a cure-all for what happened in the past, but it’s a start.”

McGill’s trip to Georgia is a case in point. En route to Ossabaw, he gives a talk at a museum in Pin Point, the coastal community where descendants of the island’s slaves now reside. As soon as he finishes, he’s approached by Craig Barrow, a 71-year-old stockbroker whose family has owned a neighboring plantation called Wormsloe for nine generations, and by Sarah Ross, who heads a research institute on the site. They invite McGill to stay the next night at a slave cabin on the 1,238-acre property, which has an avenue of moss-draped oaks more than a mile long and a columned mansion so large that the family removed 18 rooms in the 20th century to make it more livable.

Barrow, who lives there with his wife, says he grew up giving little thought to the surviving slave cabin and cemetery on the property, or to the generations of African-Americans who lived and labored there. But over time, he says, “I’ve come to an appreciation of what those people did. My people sat around having big dinner parties—they weren’t doing the work. The people who lived in those cabins sweated in the fields and built everything—they made it all happen.” Barrow also regrets his youthful opposition to integrating the University of Georgia. “I was wrong, that’s why I’m doing this,” he says of his invitation to McGill and support of the Wormsloe Institute’s research into slave life on the plantation.

The work being done on Ossabaw Island and at Wormsloe reflects a trend across the South. On Edisto Island in South Carolina, the Smithsonian Institution recently dismantled a former slave cabin that will be rebuilt for display at the Museum of African American History and Culture, due to open on the National Mall in 2015. Nancy Bercaw, the project’s curator, says the Edisto cabin is critical because it speaks to the everyday experience of many African-Americans, before and after slavery, rather than being a relic associated with a specific famous individual such as Harriet Tubman. While watching workers carefully dismantle the perilously decayed cabin, made of wood planks and crudely insulated with newspaper, she was also struck by how easily these rare structures can be lost.

This danger has influenced McGill in a different way. He applauds the Smithsonian’s painstaking reconstruction of the simple cabin, but is open-minded about dwellings that have been saved in less pristine ways. He once stayed at a slave dwelling that’s now a “man cave,” with a lounge chair, gas fireplace and refrigerator filled with beer. His quarters at Wormsloe in Georgia are likewise comfortable, as the surviving cabin is now a guest cottage with beds, a bathroom, coffee machine and other amenities.

“This is definitely the luxury end of the slave-dwelling universe,” he says, settling on a couch at the cottage after touring the plantation on a golf cart. “Sometimes these places have to evolve to continue to exist.”

McGill’s mission has also evolved over the past three years. He originally dubbed his overnights the Slave Cabin Project, but soon realized this conjured stereotypical wood shacks perched beside cotton fields. Now that he’s stayed in structures made of brick, stone and tabby, in cities and on small farms as well as plantations, he emphasizes the diversity of slave housing and of the slave experience. In talks and blog posts, he now speaks of his Slave Dwelling Project. He’s also cast his net far beyond his South Carolina base, at least to the degree that his budget allows. So far, McGill has stayed in 12 states, as far west as Texas and as far north as Connecticut. “We shouldn’t give the North a pass on slavery,” he says, since blacks were once enslaved there, too, and Northerners were key players in the slave trade, the purchase of slave-grown cotton, the sale of goods such as “Negro cloth” to slave owners, and other enterprises.

Northerners were also complicit politically, helping to craft a Constitution that safeguarded the rights of slaveholders and electing slaveholders in 12 of the nation’s first 16 presidential elections. Which leads McGill to ponder what is perhaps the biggest “big house” of them all. It was built with slave labor and serviced for decades by slaves who cooked and cleaned, among many other tasks. Slaves lived as well in the mansion, generally in the basement, though one “body servant” shared the bedroom of President Andrew Jackson.

“Staying at the White House, that would be the crown jewel,” McGill says dreamily, before dozing off at the cabin in Georgia. “I’ll have to get to work on making that happen.”