SELDOVIA, Alaska

ON a trip to the Yucatán Peninsula in Mexico during spring break, Bretwood Higman and Erin McKittrick found themselves on a beach, holding a battered tourist map. Sick of the collegiate shenanigans around them, Mr. Higman suggested they ditch the bars, take the map and walk the 30 miles of shoreline to the next town. “The beach is probably continuous, right?” Ms. McKittrick remembers him saying.

To his surprise, Ms. McKittrick, whom he had met while they were studying at Carleton College outside of Minneapolis, was game. “That was a defining moment,” said Mr. Higman, now 33; he knew Ms. McKittrick was the one.

Ten years later, they are married, have an 11-month-old son and have walked more than 7,000 miles together. “When we got together, it was more than the sum of the parts,” said Ms. McKittrick, 30. “Much more.”

Their last monumental trip took an entire year, during which they covered more than 4,000 miles of both urban and untouched terrain in Alaska, Washington and Canada by foot, raft and ski. Ms. McKittrick’s account of the adventure, “A Long Trek Home,” was published in October.