The Princeton has lots of events with no cover. There are Karaoke Nights (usually Sundays), and Trivia nights on Wednesdays. The food - much like the establishment - is simple, yet delicious. It also attracts the incredibly diverse crowd of East Van.
The train runs directly behind the bar, and you can watch goods from East roll in to the port; from there, they will be shipped across the ocean to Asia. Also, the relaxed, and diverse, atmosphere will give you a good feel for the neighbourhood.
This isn't the nicest place to walk by alone at night (there is a liquor store next door), but the neighbourhood is pretty safe.