This has probably already been suggested but here is my two cents on trying to gas up on the trail. I have never not made a mess when pouring gas from my can into my rig. So on my last build I mounted my fuel cans higher then the gas cap, now I use a siphon bulb and transfer fuel via a hose. No more mess!! I purchased a boat siphon bulb and hose then added about a 2 foot piece of stainless tube that drops down into my fuel can. This keeps the hose in place so you don't have to fiddle with keeping it in the can.