We recently did a " college tour" trip to Philly...I posted several suggestions we got from the kids at the schools and loved trying under this same user name on TA.
I'm no expert, but we enjoyed the Reading Terminal Market as a great diversion for lunch. Not only can you get a cheese steak, and hear some local musicians, but if you do it near the end of your trip, there are loads of locally made foodstuffs, and you can carry some home. We went late April, so there are likely to be even more fresh produce options for you! ( several folks from Amish country run stalls there, fudge, veggies, cheeses...yum!)
Also, there are so many art museums in Philly, we spent a whole day walking the central avenue there (ridiculous that I can't remember the name- but you can't miss it on the map! )It's a lovely park in and of itself, but on either side there are museums of every type, including a newly renovated science museum and ending with the famous Philly Museum of Art and the " Rocky" stairs.
While walking along, look for the " shave ice " truck for another uniquely Philly treat.
Do get to South Street in Philly during the day, ( cant vouch for saftey at night) a real arstsy boho scene with some interesting shops (think edgy urban hpister places, mixed with shoe shops run by newer residents, the kind of place with metal garage doors over them at night). Good eats at Jim's Steaks, and Ishkabibbles fries. These were recommended by the students,and they know
We didn't get to do more than pass by the waterfront area called Penns landing, but it looked like a nice place to spend an afternoon.
I'm assuming you'll do the National Park activities with the
ABD...have a great time, I think Philly is kind of a fun place and if my daughter doesn't stay here in Boston for college, she thinks going to Philly is number 2? But she will always be a Boston sports fan, no matter what