Murphys - walking distance decent pub grub
wickenden street is a drive but you got all sorts of food pizza-to sushi + you get the wickenden street pub great brew selection, sort of dark laid back sort of place unless they're doing raffles, then everyone gets out of control, but on a friday afternoon it'll probably be quiet or closed.
If you're looking for a sit down 20$+ entre sort of place try Cafe Noir get the chevre, bacon and onion fig tart!! I think I just made myself hungry

(dragging the wife to the show with ya? decent place to go, good service good food not breaking the bank)
If you like Thai thats byob "
Apsara" (its in the hood wear gang neutral colors) great food but its in a crumby neighborhood and the place is a bit run down. Huge menu they list about a million items
AND you can bring your own beer.
Stopped into Trinity a few weeks ago and its gone downhill in a major way - sad really.
Breakfast/Lunch
Julians on 318 Broadway
julian's providence
open 9am-5pm
They make a real good breakfast its in a good neighborhood and they have the killer beer menu

breakfast/lunch/brunch sort of place. killer food for the price
I know its not exactly what you were looking for in terms of walking distance but if you plan to grub before the show check out Julians you wont be disappointed.