The actual Appalachian Trail -- Looking at maps is great, but being there is better (and makes me feel less like a poser.) So, I hiked the entirety of the AT in GA, one day hike at a time (all but one section I hiked both ways, 140 miles total -- Hogpen to Chattahoochee Gap and back was the exception: 18 miles!!  -- ). 

These hikes tested the usability of the maps and encouraged edits.

One lesson: it'd be wonderful to have waterproof & foldable versions to carry along... but I couldn't afford the printing costs at scale.