Years ago I used to hunt in both Vermont and New Hampshire. So, this is a trip that I have made.
We used to avoid all but a very short run through New York State by heading straight for Connecticut, and then we'd 'shoot craps' on Massachusetts by driving, at the speed limit, straight on through.
Guns and ammo were always kept separate, and securely sealed in closed and locked cases. On some trips we'd leave all of the ammunition home, and buy the ammo when we got to our destination.
Depending upon a lot of different legal technicalities: At certain times, under certain conditions, and in certain places, the FOPA can be meaningless. So don't place too much trust in it. America is no longer 'the land of the free'. The 'home of the brave'? Maybe, but definitely not the 'land of the free'.