Welcome to the forums, Big!
I ride into CC from Delaware County every day. Philly drivers suck, and vast numbrs of them have neither insurance nor driver's licenses. The police seem to have better things to do than enforce traffic laws, and bikes are beneath their notice.
This is not cause to be afraid. It's reason to train yourself in "effective cycling" techniques so that you can operate safely as part of the traffic flow. I find this more important inside Philadelphia than anywhere else.
It's no worse than other big Eastern cities that were never intended for cars.
And where else can you still ride on cobblestone streets with trolley tracks?
Have fun. This is a great place.