Hey. I just finished the UPenn post-bacc program this past May. (I had previously taken many of my pre-reqs, so we're not quite in the same boat)
Honestly, all three are good schools and I'm sure they all have numerous opportunities to get involved in the community and to do research or pursue any other hobby you desire.
Quite frankly, I'd go with the cheapest, which is probably UPenn because Philly is such a cheap city. Be forewarned - Philly is also a scummy city, unsafe, and the city will try to squeeze every last penny out of you if you drive. I'm from Jersey and spend half of my time in NY and it is, all around, a far more expensive city.
Oh, and UPenn has two programs: Pre-Health (for those without experience or coursework) and Special Sciences (for those with previous coursework) and the two programs overlap.