The chili from Oklahoma! is a veggie chili, so not super filling, but they do give you a fair amount. I'd say you'll still be good with both an appetizer and entree.
The guacamole is actually good, but not mindblowing. The caesar salad was really good, and I really enjoy the burger and fries. You don't actually know how hard it is to get a good burger and fries at 10pm until you're coming out of a show starving, lol. Never had the lobster roll there, and I'd say if you want a really awesome lobster roll, Joe Allen might not be the place to go. I could be wrong, though! I'll say the crab meat ceviche was awesome, and so was the chipotle hummus. You can't really go wrong, they're a wonderful little place.