Haha, walking malls, coffee shops, parks?
Your priority should be to live in a place where you don't get shot. Live one block in the wrong direction from UPENN, and good luck to you.
I would see if there is some housing near Drexel or Penn campus, but watch for the '40th street boundary'...you get any higher than 40th street, and you'll get lots of cheap stuff but don't expect it to be the safest place. On the other side, from 30th street to 40th street are Drexel and UPENN campuses, which are good places if you can find something. Then there's a river, and across from that you'll have center city and rittenhouse square, which is expensive. (I am exaggerating a bit about getting shot, but only a bit
).
Personally, unless you want to walk to/from a mile or two each way, I'd either get housing right near campus, or move a bit farther away and take public transportation.
If you're going to be in the post-bac, I doubt you'll be in class more than 2-3 days a week, and that too for only a little bit, so don't be afraid to try to find something nice for cheaper in the surrounding suburbs and take the EL to Penn.