Hop on Amtrak, if you don't need to drive. It'll take you from Penn Station to 30th street in about an hour and a half. Other than that, there's I-95, but the traffic between DC and Baltimore, and the traffic between Wilmington and Philly are pretty nasty at times. Going for highways further West puts you too far West, and you don't want to go East into NJ and then have to go over any of the bridges into Philly.
at 10:47 AM on Jul. 8, 2011