I bought a 2016 F250,super cab,tow,plow and camper pkgs,6.2,4wd,6 speed auto,3.73-nearly the same truck you are considering. My fuel mileage varies greatly with temperature,terrain and speed.
City driving---10 to 12....frigid temp (-10 or so)8 to 10
Highway at 60 to 70,flat or low rolling hills --16 to 18,though I have done better
Carrying a tc through NH and VT ,major hilly ---12 to 14
I am in no rush,ever ,and drive in a style that gives the best mileage possible. My other vehicle is a Golf TDI which consistently gilts low to mid 40's. I prefer driving the 250 because it fits (6'4,230).