I am not an attorney. I do hold an FFL.
In theory FOPA should protect you. In practice people who have been caught in NYC and the NJ Port Authority travelling through have found out otherwise, and while the final outcome may have been that they beat the rap, it cost them a lot of money to do so.
You have an additional problem: the driving license issue from NY earlier this year (yes I read your prior posts). While you were eventually exonerated, if a NY cops runs your plate there's very likely to be a "hit" on it because information in government databases is very rarely purged. So, figure you have a bullseye on your back.
Don't take your own guns into the state. If you want to go shooting with your friend, find a range that has rental guns.

