A few thoughts....
Assuming he did camp at Bear Mtn I don’t think he lived in the city. it would be easy to catch the AT closer to the city rather than travel to Bear Mtn and start from there.
I’m thinking maybe he lived in the Newburgh/ Beacon area? Or maybe he caught the bus/ train that stopped at BearMtn for work every day? If he took mass transit from that area every day I could see him taking it to Bear Mtn and staying there.
We discussed the fact that he camped overnight in Unionville, NY. In order to camp there you have to get a permit either from town hall, or Horlers deli when town hall is closed. Town hall closes early. 1:00 if I remember correctly. Im thinking I may stop at the deli. I want to ask what information someone would have to supply to get a permit. If you have to show ID.........