I understand about driving at night and not on interstates. I just find that thinking ahead does more good than carrying a 5 gallon can with me. I get between 7.5 and 10mpg, and I have 2 tanks that hold 30 gallons each. So, I know I'll get at least 450 miles on the two tanks. I fill up both tanks upon departure, and I fill up before leaving the last major area (or before leaving the interstate). I never let both tanks get to empty - I always have at least 1/2 tank. That means I always have at least 100 miles worth of fuel. That 5 gallon can only gets me 37.5 miles.