OP here, purpose of question was the up coming trip is 300 miles out, 300 miles back. Have an 80 gallon tank @ 8mpg, should be able to complete the trip on one tank. I'm not a fool, will plan on filling up on the flip. Question was if I'm going to be surprised by dropping to ..say 4mpg, I probably need to locate a truck stop or large gas station on the way out, and plan to stop there again on the way back. First trip with the toad, I don't like surprises. Also don't like searching for appropriate sized gas stations while traveling. Did that once with my 5'ver and almost ran out before I found a diesel station. Consensus seems to be I won't lose more than 1 mpg, so I will stick with original plan. Thanks All !!