To my knowledge, the only rail commute to Philly exists on the "Speed Line", which terminates in Lindenwold, obviously not even close to Mullica Hill. Then NJ Transit goes from Lindenwold to AC. There is one bus line that runs from Mullica Hill on NJ Transit, the 410.
http://www.njtransit.com/pdf/bus/T0410.pdf
Unfortunately, this bus only gets you to 6th and Race. This is basically at the foot of the Ben Franklin, at the Constitution Center. Then, I'd imagine you'd have to gallop a few blocks down south to Market, and pick up PATCO at around 8th and Market. I've been on this ride a few times with friends when we wanted to drink in the city and not have to drive until we had sobered up some back in NJ. It's pretty harmless. But I've never been on the 410!