Off to Philly and Need Some Info

Hello, I just realized that I am leaving for Philadelphia in a week (for a conference where I'll be presenting along with my boss to about 100 people - yikes) and I need to get some information on where to go. I mean, I know where my hotel is and all that, but I need to know WHERE TO GO, like from locals or people who have been there and had great food, fun, etc. First of all, where do I find the BEST philly cheesesteaks? Not the ones all the tourists hit, but the ones the locals drive out of their way for, kwim? I'm staying downtown near city hall and won't have a car, so wherever you tell me to go needs to be in walking distance, short walk from the train or bus accessible. Secondly, where is a good place to go to waste a good Sunday afternoon/evening? Same thing for Wednesday?

Any and all advice would be greatly appreciated. Thanks.