My fave were those red, old-tyme Coleman 1-gallon white gas cans with a screw on metal lid. I just don't like the idea of storing gas in an enclosed passenger space.
The cans would just fit in the space in front of the wheel well accessible through the little doors near the floor. Out of sight, out of the box, good air circulation, not going anywhere, there when you need them. If going to elevation, we would not fill them all the way and push the sides in to allow for expansion when getting up higher in elevation. We always try to figure out how much gas we need for a given trip. If more than 2 gallons, we would refresh the cans when fueling up the truck. We have a Honda 2K which sips fuel. More and more now with our 'solar array', we find we don't need a generator along so it stays in the garage to be used on a wagon when electric leaf blowing our 200' driveway. No micro wave. No air conditioner. Depends on the trip.
jefe