Did a run with the camper this weekend from Draper, UT to Vernal, UT and back.
We were headed for full-hookups, so no water or generator so the load was around 7200# I guess. Ran 60-65 mph and got 8.1 mpg on the way out and 9.2 mpg on the way back.
I still grin when I have the cruise set at 63 mph, we hit a 12 mile grade of 6-7% and the truck settles into 4th gear @2700 rpm and just pulls.
oh, and here is the elevation profile
2013 Screw, Race Red, XLT trim, Ecoboost, 4x4,
3.55 E-locker, Michelin LTX M/S2 LT275/70R18E tires,
Firestone Air bags in back, Windbag behind the wheel
dragging a 2013 JayFlight 26RKS up and down the Uintas