all of the above,, I get 14 to 15 fully loaded with trailer on the interstates. On two track it is around 9 to 10 mpgs in low range. If I'm in high range on two track the same as highway mileage. We are set up for about 5 days in the back country till we have to find gas, water, food and beer. The fuel tank has 27 gallon capacity and we,carry two 5 gal jerry cans. I never go in without topping every thing off.. at that, even if all we are doing is low range we still have well over a 250 mile range.. There just aren't many places in the lower 48 where you can travel 250 miles without coming to a town or gas station.