Whereabouts 'west' of Philly - there isn't a whole heck of a lot except for the above mentioned KOA in C'ville, which is about 45 miles west of town, and does offer guided tours of the city. There is public transport, of a sort, from the western suburbs there, if you look for SEPTA schedules and routes. Look for the REGIONAL RAIL line, the Thorndale route. It runs in along the Main Line from out there. Commuter routes will take you into center city ("Suburban Station", not "30th Street") where you can easily find a taxi or even walk down to the Indep. Hall/LB area. The good thing about Philly's center city area is that it's relatively small - Suburban Station is only about 12 blocks from IH/LB area. The Art Museum/Franklin Institute and Natural History Museum are a dozen or so blocks in the other direction. I think they're about finished cleaning up after the Pope's visit, so the roads should all be open by this weekend.
http://www4.septa.org/maps/system/index.html