I've driven thousands and thousands of miles on long trips in trucks without working fuel gauges, sometimes odometer too..
Easy way to do it is bring 5 or 10 gallons with you, drive until it sputters, cut it off quick and put 5 gallons in the tank, head for a gas station.
You'll figure out soon enough by experience how much you can put in your tank, and then about how many miles you can drive, and before long the extra 5 gallons in the bed is hardly used, (but don't get rid of it, then you'll need it).
Grigg