as far as i know (i'm a first year at rwj), everything secretmiss said is right on. everyone is in piscataway for the first two years, then about 1/3 goes to camden.
as far as switching, you can ask the admissions office to put you on the alternate list for piscataway...i did that last feb, and within a few weeks they offered me a spot in piscataway, although by then i had decided i wanted to stay in the camden program.
basically, there are strengths/weaknesses in each program. camden, obviously, tends to be good for EM/trauma, while piscataway is pretty strong in IM, peds...just as examples. although, if you guys have seen the match lists, it doesnt really seem to make a huge difference.
i think for many people it comes down to location (and also, i've heard really good things about the dean for the camden program)
if you are undecided, the best thing to do is to put yourself on the alternate list and try to go to the accepted students mixer in camden so you can get some more opinions.
hope this helps 🙂