Do you then fill up in Mammoth Lakes for the return trip?
I used to fill up in Bishop even with the meter reading more than 1/4 tank (my usual refill time on long trips) at Safeway or the Indian Reservation. That would give me enough to make it up the hill, drive around for a week, and still be able to make it back down to Owens Valley without buying higher-priced fuel in ML. With the winds in the right direction. I could make it back to the Reservation gas station at Fort Independence.