Too bad, Well, if your going to be in the city mostly, all the museums that have been mentioned should be prioritized. In the way of painting, the Philly Academy has the great collections of landscapes and Eakins works as well as Anshutz Cropsey etc. The Phila Museum of ARt is a real mixed bafg of everything from Egyptian to Modern. The Franklin Institute is neat , but if youve no kids to bring along, youll be a little bored Im afraid. Academy of SCience is also one big nature museum so If youve seen the Smithsonian or the Field or The Museum of NAt History , youve seen better than Philly ACademy of Science.
BUT, Only Philly has gut the Mutter Museum, a world class collection of weirdness in the medical sciences that people take sanitizing showers after theyre done at this one. Theyve got examples of the Bubos from people with Bubonic plague, Theyve got diseased and deforemd body parts that would gag a maggot.
The CAmden aqauarium is a good trip across the river and youll get a chance to see all the mothballed naval hips like the Olympia,a couple of WWII subs, a few square riggers and an old steamer. If youve got a car, a ride down to the Philly NAvy Yard is a treat. You get to see several of the WWI and WWII and later era ships of the "Line" in mothballs.
Le Bec Fin is still the best restaurant in Philly, but there are several really good ethnic restaurants besides Italian, theres a really good Chinatown selection, a great Russian and E European section, (our fav is called WARSAW).
The 4th celebration will be down by the waterfront I believe , so you Will get a hance to see the old ships.
Get a Cannoli at Isgros on Christian St (in the Italian MArket section) AA These places in the Italian MArket are open pretty much the time and are bustling hawking produce and cheese etc six days a week.