Tap, I don't know what States you travel through but you may want to consider mounting the safe somewhere less accessible to the driver and passengers than under the seat. That may be a grey line under some the laws of some States.
We took the multi state concealed carry class and we understand the laws. The class was excellent and pertained strictly to multi state concealed carry. The instructor taught in many states and was a wealth of knowledge on firearm laws.
Vehicles like vans and SUVs (which don't have trunks) may transport firearms and ammo inside the car.
Some states require that ammo must be in a separate, compartment and also locked and located as far from the driver seat as possible.
We also bought a book that lists all 50 states and their firearm transportation and carry laws.
The laws are complicated. New York state for example, allows TRANSPORT ONLY thru the state...a non resident cannot even stop for overnight lodging if in possession of certain firearms.
Our instructor was once driving thru NY to a competition shoot and she had major car trouble and needed to get a motel for just 1 night. She notified the law that she had firearms...they made her FedEx ALL of her guns back to her home...SHE COULD NOT EVEN STAY 1 NIGHT INSIDE THE STATE WHILE POSSESSING FIREARMS! She said it cost her several thousand dollars to overnight ship the several guns home. I believe her story.
Any time we travel to a different state, we will recheck the current laws.
Sent from my SM-G935V using Tapatalk