No you're not. FOPA requires a direct route, but a direct route does allow for stopping for gas bathroom breaks and meals along that direct route - or just off it, such as exiting the interstate to eat at a restaurant just off the interstate. Now in a dinky little state like NJ, you normally would not stop over night, but given that you might have to drive from VA to VT or ME, with no real friendly firearms state sin between, you may have to stop somewhere, especially with NE corridor traffic being what it usually is. That's also allowed under the pass through provisions of the FOPA.

I agree, if you decide to go visit a relative, tour a museum, etc, that would not meet the requirement so the pass through provisions of FOPA.

I do however agree with you that an over zealous and under educated officer may not be aware of FOPA's pass through provision, but one would hope an officer would still have probable cause to make a stop in NJ. Even if a stop occurs, a firearm is found, and FOPA is ignored, you'll get hauled downtown but a call to your lawyer will get it sorted out pretty quickly unless you did something stupid - and actually illegal - like resist arrest.

NJ law can be what ever NJ wants it to be and can inflict it on their own residents, but federal law is in fact preeminent.

Just be prudent, follow the letter of the pass through provisions to a tee, and take care not to do anything that would be probable cause for a stop, and if stopped don't do anything that would become probable cause for a vehicle search.