Based on what I've read here, I (an Amtrak enthusiast) suggest utilizing the "Trenton shuffle". I have done it (once; I'm an Amtrak enthusiast), and it was as easy as portrayed, as well as cheaper than Amtrak.
Originally Posted by
schriste
Your SEPTA train will also continue on to the 2 center city stations which might be more convenient.
It used to be, and as far as I know still is, the case that an Amtrak ticket to (or from) 30th St Station was good for a ride on SEPTA from (or to) 30th St Station to (or from) Suburban or Jefferson stations. Corrections welcome if my information is out of date. If I recall correctly, I had some inconvenience at the SEPTA entry points because I needed to show my ticket to a gate attendant (and therefore find a gate attendant) because the turnstiles would not accept the Amtrak ticket.