Tracks (1976) was made on Amtrak passenger trains without permission, so Henry Jaglom, Dennis Hopper and the whole crew were regularly ejected.
Director Henry Jaglom said that for him, the whole story could just be taking place in the mind of Dennis Hopper while he's sitting on a bench.
Although not noted in locations, the last 10 minutes were filmed in Paso Robles, CA. The Acorn Building on 12th and Park is clearly visible as Hopper exits the ice cream shop and heads west toward Spring Street. Also the funeral scene was at a Paso cemetery.
Dennis Hopper and Dean Stockwell later appeared together again in Blue Velvet.