Last month i had my tt loaded heavy for a week camping trip. I had the entire cab loaded with gear for the trip. Too much to list it all. In the truck bed i had a lot of firewood, kids bikes, ez-up, chairs, etc
Wife and kids had to go in her car separately. No room in the truck and I have a crew cab.
Trailer was probably around 6k plus all the gear and me in the truck.
I have the 6.4\3.73 gears.
Even if the dash monitor is off a little, I averaged 11.3 MPG. That includes some highway and some mountain roads getting to the CG. Considering the truck has 2300 mi on it, I thought that was pretty darn impressive.
I did run around 60 on the highway and kept it in M5 so all 8 holes always stay lit.
Unloaded on the highway I average over 19 MPG. It's no diesel, but gassers have come a long way.