Scholz's Beer Garden is a great idea. They can do a private banquet room for y'all. Or the Salt Lick (yummers!), but you will need to drive.
I would not show up at Scholz's without calling ahead or reserving a banquet room, even though it is huge. Scholz's is very very popular with groups such as yours. Last time I was there, two large parties took up the entire place.
http://www.scholzgarten.net/banquet.htm
Believe me, you do not want to just go into a restaurant without calling ahead to see if they can accommodate you, even if it is a cafeteria. It will not have enough kitchen help to put your food out all once. I work with an organization that hosts a luncheon for 80+ every month and boy oh boy it's tough to do. Sometimes we rent a non-restaurant venue and then hire a caterer, it's that difficult. Also, many restaurants will nickel and dime you for every little thing.