"If you can get a copy of "hobo" the film by John t. Davis...its pretty epic.
Also if you want to touch on squatting and punk culture "suburbia" it's an oldie but a classic:
Both a bit dated but classics
fuck finally i was wondering why noone mentioned hobo yet, yea its old and quite a bit dated and kind of slow but its deffinetly a classic. what about "long gone" or "emperor of the north pole" thats a fucking gem right there. i think long gone is my favorite train doc that ive seen just for that one line thats something like "heres yer stick john". plus theres some footage of new york slim which is fun because that guys a king, and not to mention dogman tony and his wife who was later dated by another 'bo i will not mention and all the other old ftra people in the movie.