And personally I'd want a lot of that stuff locked inside a cab, and not in the bed, save for fuel and tires. Fuel wise tho the supercrew should be GTG without many/any additional cans. Hard to find 36 gal+ factory capacity outside of pickups in the USA.
36 gallons is nothing. Figure an average of 6mpg in a true off-road overlanding situation, that's only 216 miles to empty. Now factor in leaving the truck running/idling while clearing debris, getting un-stuck,etc. I'd want at least 50 gallons.