Reading Terminal is a must-see, although hours are limited (8a-6p Mon-Sat, closed Sunday). Check out Chinatown, also.
A "steak wit" is the best way to go. I had thought cheese wiz would be gross, too. But once I tried it, "wit" is it! Went to both Pat's and Genos.
Have fun. I definately want to go back and "go native."