Hauling some handicapped pool lifts and stone for work. Far and away the worst mpg I've ever had towing.
I don't think this load was even over 5klbs but that box trailer has the aerodynamics of a brick. It's like towing a big parachute down the road. I hauled a 3k+lb flat bed with three 2klb+ pallets of tile on it for a total of 9-10klbs on the same drive and got 12.5mpg
Hauling the same trailer in January loaded with furniture.
I wish I had been taking pictures the other day at work. I work for a hotel company and were getting close to opening the project I've been working on, so we were bringing over all the stuff that goes in the building like the linen, carts, and other pieces. When we got to the pallets of linen and towels we had two 20 foot flat beds towed by my max tow king ranch and my coworkers max tow lariat loaded from end to end and side to side with pallets of stuff. It looked like the clampetts rolling down the road, the only thing missing was grandmas rocking chair strapped to the top