When I was that age, I did a bunch of hunting. The best hunting on public game lands was only accessible on foot. I knew trails and shortcuts you would never find on any road map. USGS maps and aerial photos make it a snap to do land nav these days, even more simple with GPS.
He may have done the same sort of hunting.
Plus they’re saying he was a re-enactor with some group that followed an Eastern European extremist group, whatever that means.
This area is my neck of the woods. Pretty rough country. Lots of un occupied camps and homes all over the place. He could rough it for a while. Once it gets cold and the snow starts to fall, the game will change. Unless he has a game plan, my guess is that he will be found taking a self induced dirt nap.