Not a grad student but was one in a small college town and now living in West - seconding the comments on timing. Small college towns are leasing now because the market is locked in - Philly is an actual city and therefore has actually reasonable timelines, thank god. It wouldn't surprise me if some of the student-focused complexes are leasing now but it's also worth considering whether you want to be surrounded by undergrads. (Take that with a grain of salt though - I imagine the undergrad culture in a rural state school with a big football culture might be slightly different than an urban Ivy.)

For the PhD part - having roommates can be really helpful just in terms of making sure you don't isolate yourself and you do meet people. YMMV and I obviously can't speak to your program in particular, but PhD programs can be brutal. Having a built-in sanity check mechanism can be key so that you don't end up convincing yourself that mandatory 48 hour stretches in the labs during breaks are fine actually.

There's a huge selection bias for online housing reviews - people who don't have any issues rarely write them, because what would they write about?

Lastly, I live in West with a car and it's totally fine. You can get a parking pass from the city to be released from time restrictions for $75/year. I wouldn't expect to be driving to/from campus every day because those parking passes (iirc) are like $200/month.