There's the Septa West Trenton station on the West Trenton line that is 1.5 miles from the terminal - either a $5-$7 cab ride once you are there (look up cab companies beforehand and call them) or if it's a nice day and you have little luggage, a 25 minute walk:

http://goo.gl/maps/pDymy

Trains head there from Center City every hour on the weekends and every 30-60 minutes weekdays. It's about an hour from Suburban Station. Round trip ticket is $17.50, although it is free on the weekends if you have a transpass/trailpass, and free almost anytime if you have a zone 3 or above TrailPass (except trains arriving into Center City before 9:30a or departing Center City between 4p and 7p).