Tom Gathman, a.k.a. The Real Hiking Viking, hasn't seen most of his own face in two years, but he's seen more of North America's trails and vistas than just about anyone else. The impressively bearded Marine combat veteran ditched his car, his apartment, and most of his worldly possessions to pursue a way of life that has also become his living—as a full-time professional hiker.

In 2013, Gathman, 32, was invited to hike the 2,185-mile Appalachian Trail for the Warrior Hike's Walk Off the War program (he'd done two tours in Iraq, the second in a scout sniper platoon), and the experience of walking from Georgia to Maine was a game-changer. In short order he'd quit his day job and started a new one, chronicling his free-range way of life and inspiring others to "hike their own hike" through his deeply enviable Instagram pics and Facebook updates.

The next year he tackled the Continental Divide Trail, a grueling 3,100 miles between Mexico and Canada, and in 2015 he racked up more than 3,500 miles trekking through parts of the Pacific Crest Trail, the Florida Trail, and the Arizona Trail.

"It's an amazing way to live," says the Pennsylvania native, whose goal for 2017 is to complete the Triple Crown of thru-hiking—the AT, CDT, and PCT, nearly 8,000 miles total—all in one calendar year. "You don't have to be a consumer. You don't have to have a 9-to-5 to be happy. You don't have to have stability in order to be comfortable in life."

If his perspective has you thinking about quitting your job, living moment to moment and mile to mile (preferably with the help of corporate sponsors), here's what Gathman says you can expect out on the open, rugged, relentless trail.

To lose a lot of weight

Gathman loses 40 to 60 pounds in an average seven-month hiking season, occasionally helped along by waterborne parasites like giardia. He rarely filters his water, and gave up his camp stove in order to travel even lighter. "Whatever my stomach tells me looks good when I get inside a grocery store is what I pack to eat." At an average pace of 30 miles a day, Gathman guesses he burns about 7,000 calories, which is hard to replenish with trail mix. "Sometimes I literally drink olive oil for the fat and calories."

To make your peace with pain

On top of his garden-variety blisters, sore muscles, and fatigue, Gathman has hiked more than 300 miles on stress fractures, and dozens of miles on torn cartilage in his knee after a 100-foot fall on an icy trail. "I've had days where each step—each and every step for 30 miles—I've felt like crying. I've prayed to God for strength; I've begged God to take the pain away. And I don't cry. I think 99 percent of humans would bail on what I've put myself through. But make no mistake, it's self-inflicted. And I plan to put myself through worse."

To fight off the occasional bear

After Gathman's camera caught the attention of a feasting black bear, running away from the animal—highly ill-advised, Gathman admits—didn't work. "It got within 20 feet of me, and I thought, ‘This is it. I'm about to get my guts ripped out of me while I'm alive.’ ” And of course he doesn't carry bear spray or even a knife. "But I wasn't going down without a fight, so I turned around and charged at the bear with my trekking sticks, screaming at him, probably foaming at the mouth. And it turned and ran. It stopped at one point and stood up on its heels, and I just kept running at it. That was the most terrified I'd been in my entire life, including getting shot at in combat."

To be forced to drink your own urine

Under the scorching New Mexico sun, Gathman found himself close to heat stroke, having run out of water on a 35-mile desert hike, still six miles from the next water source. That's when he felt the sensation that he had to pee. "Without even thinking about it, I peed into my bottle and screwed the filter onto it and drank it. It was the most disgusting liquid I ever tasted in my life. I probably swallowed a few drops of it and spit the rest out. Experiencing that kind of thirst and the realization that I just drank my own urine gave me the mental fortitude to decide that I was going to make it to that next water source—which turned out to be contaminated."