In my opinion, Matt and Sweat are not together. I think it would be much harder for 2 of them to blend in anywhere...as it seems most people are looking for a 2 people. Also, I don't imagine these 2 as BFF's, rather they used each other as a means to an end.
As for the railroad angle, correct me if I am wrong, but isn't there a whole sub-culture of people who ride the rails? I hope LE has tried to get the info and pictures out there to that sub-culture as I am sure one of them would be happy to give up these 2 for $100,000.
Regarding the Adirondacks....there are infinite places to hide!! Ugh. So many trails heads, lean-to's, empty cabins, tree-stands, hunting cabins and isolated areas. There is just a plethora of places to go undetected! Uhh... I wonder if they have checked Israel Keyes old cabin in Constable, just 40 miles away (that just occurred to me).
Also, if they carried a tent in the guitar case they would probably be all set for a good long while. Interesting that they chose this time of year to escape, when the Adirondack's are not quite yet populated with summer folks yet warm enough to easily survive outside.
Those are just some of my thoughts...more to come, I'm sure!