Tonight I had the chance to tow for a decent distance so I thought it was the perfect time to see what she'd do.
Truck: Regular cab express, 2wd, 3.55 gear, tonneau cover, afe intake, Super Turbo Muffler. That's all I can think of that could be related to mileage.
Load: Single axle landscape trailer with dovetail and shorter gate. It has a blower rack loaded with a backpack blower. I had my ZTR on there as well. Overall it weighs about 2,200lbs.
Conditions: Partially flat to rolling hills, 65 degrees. Drove 70mph for most of the trip with sections of 50 due to construction zones. I used cruise control and turned "tow/haul" mode off since it's a relatively light load and I had no stop and go driving.
Results: 18.14mpg hand calculated.