When I confessed my increasing restlessness with my husband, he admitted he, too, had already begun churning up plans for when we returned to the work-filled, frenzied days in New York City that we had been so eager to flee. Why can we never recall this cycle of hypothetical plans and daydreams until we re-enact it yet again? “One merely speculates,” Mr. Aciman writes of imagined other lives, “and seldom does any of it have anything to do with the real world.”

My tendency for mere speculation about living in Chile may be partly fueled by how few visitors from abroad we come across during our weeks in Limache. Unlike in other parts of Chile, it is an area without much of an established tourist culture. An hour’s drive to the coast, in the port city of Valparaíso, clots of foreign visitors form along every colorful wall mural and picturesque overlook of the ocean below.

But the lush quiet of the Aconcagua Valley isn’t a draw for international tourists. In the town square of what’s considered “new” Limache, families rent pedal cars for children to circle the sidewalks under the trees. During our afternoons escaping the heat, we often come across families from Santiago visiting relatives in the area, or former Santiaguinos who have moved there for more room and a reprieve from the traffic and air pollution in the capital.

At an hour and a half’s distance from Santiago, Limache occupies a similar option as a commute from Hudson, N.Y., might to someone with a job in New York City. As in upstate New York where people with city salaries move in and drive up costs, the rising number of Santiaguinos buying up land in Limache has created tensions. Soon enough, I start to fixate on these larger questions — how our half-Chilean, Brooklyn-raised children might be received at a local school. At what age would the insidious role their mother’s country played in the Pinochet dictatorship begin to come up with their friends? What if we went through with the move and weren’t able to find jobs, or found ones, but they didn’t last?

By the second Sunday, with the vapor of our daydreams beginning its inevitable fade, the complexity of the move is increasingly plain. It becomes obvious how doggedly our inner conflicts would accompany us here, as inner conflicts accompany a person anywhere. While we pack for our return to our one-bathroom apartment and the whirl of the spring semester about to begin, I remind myself that Rainer Maria Rilke’s injunction “you must change your life” is really about a shift in mind — not geography.

And yet, on the hectic January mornings in Brooklyn, bundling up in hats and scarves, my throat tightening at whatever news spewing from the White House I managed to read before getting my children out the door, what prevails in my thoughts of our weeks in Chile is never my increasing sense of restlessness there. It is the little stream in La Campana National Park in nearby Olmué where my spouse and I hiked in our early 20s when I was teaching in Valparaíso and he was finishing his master’s degree. To see our kids playing on the same rocks we crossed two decades ago takes my breath away though we return to the stream every year.