Campervan Insurance

I have a VW Eurovan that’s already run out of gas twice. So the prudent thing to do is to travel with spare fuel. This way if I run out of gas I can just coast over to the side of the road, put an extra gallon or two in the tank, and continue on to a gas station. The problem, of course, is that gasoline A) is highly flamable and B) generates lots of fumes. Traveling with two gallons inside the van is a bad idea. So what is the best thing to do?