If you take the RR1 train in from the airport, the inbound will probably not be bad, and the outbound later will be after rush hour.

Get off at Suburban Station and come above ground - there is an amazing maze of tunnels which can get you all over the place, but also get you pretty lost!

You are at the very center of town there. City Hall is the old building; you probably cannot see the statue of William Penn, the founder, on top. I used to love walking through City Hall - sidewalks just go right on through, nice courtyard - but when I was there this spring it was closed up and under rennovation.

There is a place near the station where there is an outdoor skating rink, if that is still in operation. It was on JFK Bouldevard and can be fun to watch. You can walk east on Market Street to the famous old Independence Hall. It will be closed but maybe there will be enough light to give a good look at it? That end of Market street is not nearly as upscale though as the other end, as mentioned above.