When I was towing with gas I carried only because I had gas cans for the toys. When I went to a diesel TV the first thing I did was add an auxiliary tank that let me go 700+ miles between stops. The MH carries 90 gallons of diesel and gets a solid 10 MPG so with around 900 miles between stops I have not seen the need for extra fuel. I still carry gasoline cans for the toys but are useless to my TV :(