A months-long hike of the Appalachian Trail often involve long-term preparation and life-altering decisions. Would-be hikers leverage institutional knowledge from literature and online forums to physically and mentally prepare for such an arduous hike. Their use of social platforms provide useful insights on motivations for undertaking the thru-hike, how they deal with unexpected conditions on the trail and understand choices made in conditions of scarcity. By analyzing over 100,000 Reddit posts and comments in r/AppalachianTrail and applying a Sense of Community theory, we sought to understand hikers' identity as community members, how their emotional and practical needs are met, and how they evolve. We found that the role and language of thru-hikers change as they progress from pre-hike, on-hike, and post-hike stages, from a questioner early on, to an expert post-hike. We conclude with design recommendations to support offline communities online.