[jyl]

There is a cargo "well" in the roof above the driver and passenger seats. I could strap a flattish container there. But it would be exposed to sun etc. There isn't another natural place to mount a gas can on the exterior.

I was thinking a couple of 1 liter aluminum fuel bottles like you use for camping, packed in a sturdy steel box (like an ammo can), bolted to the underside between the frame rails or to the floor under the rear bench seat cargo spot. Deathwish?