My work truck is a 2016 4x4 2500 Chevy short box double cab 6.0 3.73 gears with a ladder rack and loaded close to gvwr.
It gets about 13.5mpg with e0 premium and maybe 14.5mpg or a bit better with e10 regular. E85 is about 11 to 12.5mpg. And yes I drive enough and varied enough that those are fairly good numbers and those e10 and e0 numbers are not what I have expirienced in other vehicles.
My suburban got 10 something the last time I figured it.