Hellobee Boards

@Kitkat: what types of things are you looking for? I live outside of the city and work in the city so I have plenty of suggestions. Since your baby will be young you don't need too many baby or kid specific things, even though Philly has plenty of those.

You will have the best time! Feel free to wall me for more, but just sitting outside at Parc on Rittenhouse Square with the stroller is such a delight. Even though there are tons of great restaurants, it's a pretty lowkey city and you can bring a baby to the majority of them. I'd personally look for an AirBNB around Rittenhouse/Midtown Village/Washington Square/maybe Society Hill to be close to Historical attractions AND the heart of the city.
Eastern State is awesome around Halloween (so scary!) and not too far from some of the most wonderful art museums (Phila Museum of Art, Rodin, Barnes).
There's a walking/bike path along the Schuylkill River that takes you right past the PMA, then on past Boathouse Row and onto Kelly Drive. It's really beautiful and gets you into Fairmount Park if you are into walking/hiking (one of the largest urban parks in the US.)
In Center City, the bus is great (like if you wanted to go from the historic district/Independence Mall area up to Rittenhouse Square for more shopping and restaurants and then on to University City where Penn's campus is), but the subway only runs on one line (from the Stadiums to Temple University, if ou planned on any sporting events at either location) so to get to more far flung neighborhoods it's not convenient to use public transit. But, if you plan to take daytrips (Princeton for ex.), regional rail/NJ transit trains are easy and inexpensive.

Reading terminal market is great for a yummy lunch. Princeton is a cute town, the university is nice and there is a little art museum, you could get there by taking the Trenton line on regional rain from 30th to Trenton then transferring to NJ transit to Princeton. Philly art museum is really nice, I love the mutter museum of medical oddities but it's an acquired taste, penn has a great museum. There are lots of walking tours throughout the city if you want more organized things but most places you can get access to on your own. The mint is neat, you can see money being made. I would recommend the constitution center to round out your history bits, it's a well done engaging museum. Septa, the public transit system is fine in center city before about 11pm, much later and service gets spotty same with trying to be outside the center city area. Valley forge would be about 30-45 drive and is gorgeous in the fall, lots of walking trails and history. Lancaster county is Amish country and is about 1.5-2 hrs away by car, while I go there a lot it's to visit family so I do nothing touristy.

We went there last fall and had a great time. We did Independence Hall/Liberty Bell, the Constitution Center, the US Mint, the zoo, art museum (for the art too, not just the Rocky steps!), and Valley Forge.

I loved Independence Hall and Valley Forge. Valley Forge was way neater than I thought it would be. Buy the audio CD/guide at the gift store first, and then listen do it as you drive through the park. It takes about an hour I think and gave so much neat info. Also, it was really beautiful in the fall.

I thought that the zoo was really fun too, but DH and I are big zoo people.