I've got the 36 gallon tank on my 13 F150. Love it! I had the 26 gallon tank on my old 97 F150 and would usually have to stop for gas at least once on most of my local camping trips (3-4 hour one way trips).
I too like to stop every couple of hours to stretch the legs and take a wiz.. But, rather do it at a rest stop instead of trying to find a gas station..
Also like going 2 weeks between fill ups on my daily commute instead of the weekly fill ups with the old 97...
Anyway, won't get less than a 36 gallon tank ever again!
Mitch