2000 F350 DRW 4x4 7.3L (modded)
@50mph 26-28mpg unloaded 17-18mpg loaded
@65mph 22-23mpg unloaded ??loaded? I don't drive that fast with camper.
I got 32mpg once on a long flat stretch, unloaded with a tailwind....but it took highway tires, 90psi, and some attentive driving. I just wanted to see if I could break 30mpg.
For long trips I plan on 15mpg loaded, and calculate my fuel stops accordingly. I've averaged 17-19 going up the alcan loaded with a 20' trailer (sig pic). I've also hit strong crowsswinds/headwinds (50+mph) before and gotten 9mpg on a trip to Anchorage.