He wasnt "alone". He was getting food somewhere. He had lots of stuff he couldnt make himself. And someone had contact enough to report his location. Id bet he was stealing from locals.
He was also living near his hometown. So “cut off” is a bit less likely than mostly under the radar.
These two environmental conditions can have varying impacts on a person's mind.
https://www.theguardian.com/world/2013/apr/11/american-hermi...
He stole food and propane tanks from the vacation homes in the area. When he was eventually caught and put in jail for all of the theft people remarked at his strange use of language. They claimed he talked like a book.