Another thing to consider is that many rifles that are legal in Pennsylvania may not be legal in NJ. This is thanks to NJ's assault weapons ban (passed before the national ban, and it is still in effect). Many of these rifles are listed by statute, some are described merely by cosmpetic features (such as grip styles, stock types, etc.).
As the other two said, you can only buy handguns from your state of residence, so decide which state you want to live in (yes you can do a state to state transfer, but it'll cost you in transfer fees, and possibly shipping as well).
I'm not afraid of the guy who wants many guns; I'm afraid of the guy who wants just one.