Dan wrote:

I am debating whether it's safer to leave my 396 in the plane, or take
it with me in a rental car

that's a service I would like to see at FBOs: lockers. A safe
place to lockup your gear, to protect it not only from
possible theft, but also from the heat. I have seen that only
once so far (at KGCN)

--Sylvain