You might want to check with the PDRNJ State Police or Attorney Generals Office on LEOSA and hollow point ammo (fine is/was $1000 per round-Hornaday Critical Duty isn't considered hollow point). The same for New York on the magazine thing/LEOSA. Allow lots of time for replies.

I'm afraid with many of the states you pass through the attitude will likely be to detain and let the prosecutor sort it out. Several years back I was trying to figure out how to lawfully attend a training school in Maryland. No one would put anything in writing and I finally decided the hassle/risk wasn't worth it.

The gent below reminded me about Mass&**^(*). You cannot leave a firearm unattended in the vehicle if you're passing through. Do your potty break before you enter the state and don't stop till you're back in the US. This is what I did enroute to New Hampshire a couple of times.