You may have already thought of this, but you could take the Bolt Bus / Mega Bus from 30th Street in Philly to Harrisburg/State College/Pittsburgh. I realize from those locales you'd probably have to take another form of transportation to a trail head but maybe you know someone in one of those areas that could shuttle you.
Another option I thought of was the Bolt Bus from the Cherry Hill Mall to NYC and then the Trailways Bus to the Catskills at Woodstock, NY. Would probably still cost around $100 round trip though.
Could stay local and hike the Batona Trail through the Pinelands but that's neither disappearing nor would it take more than a couple days.
There's a Metro North stop on the AT in Pawling, NY too but you'd still have to get to NYC first.
So in summary, yeah, it's not easy to escape from south Jersey.