Right there with Lincoln Financial (where the NFL Eagles play) and Citizens Bank Park (MLB Phillies), its about 10-15 mintues out of the city. From Hotel Monaco, which is right there at Independence Hall, you're looking at about $20-22 in cab fare.
The place looked like it had quite a few restaurants in it and even had an area where a live band was playing which was pretty cool.
If you take a cab and are wanting to catch a cab back after any kind of show, get down to the main roads by the train stations.....and it would help to leave a bit early if you want to catch one quickly. We left one song early and caught a cab in about 5 minutes once we reached the main road.
Looked like a lot of people were using the train, so I imagine thats a viable option as well.