In Philly consider Independence Hall, Liberty Bell, Reading Market (food), Philadelphia Museum of Art, Franklin Institut
Betsy Ross and Benjamin franklin homes, and old north church.
Valley Forge Park is NW of town. And definitely have a genuine Philly cheesesteak sandwich. My daughter and I did a cheesesteak challenge trying several recently. We loved an Amish Breakfast in Reading Terminal market, but there's tons of other great unique food options there.
I'd be happy to give you a call if you like. I agree with others on Gettysburg, and inner harbor/Fort McHenry in Baltimore. The Naval Academy is also close by in Annapolis. We lived in the area for 7 years.