Where is the closest parking? What are the chances there will still be open space in the lot around 10am?

Tons of open lots all over Philly, just search 'parking lots' in your gps and about a hundred little icons pop up.

I parked at a place by Penn's landing, $17.00

There are several parking garages within an easy walk.

Take the train. Its 4 blocks from Jefferson station

The Philadelphia Bourse on 4th has a parking deck near by. I don't know what rates are but that's definitely an option.

There three parking lots around 22nd and market st