Hi! I've lived in the Philadelphia area (about 30 miles north) for over 30 years. I can't add much to the suggestions about attractions within the city (and they're all good), but if you're interested in visting areas outside the city, I would suggest the Valley Forge National Park. It's a national historic park. Valley Forge was the site of the 1777-78 winter encampment of the Continental Army during the Revolutionary War. It's a lovely, wonderful park whether you take a driving tour or hike the many trails through the park; there's a museum, monuments and historic houses. Well worth a visit.