Comparing mileage figure when towing is pointless. We need a baseline of driving the truck unloaded, preferably a nice long freeway trip, to get any sort of baseline.

For example, my wifes 2011 1500 will get anywhere from 6 to 20 mpg depending on use. Avg daily driving nets 16. My 92 Cummins avg 18, my 77 Wagoneer avg10