I get 10.8 to 11.8 mpg consistently, towing a 3500 lb loaded trailer with the Ranger. It is a 3.0V6. I think the F350 diesel would do just as good but is too big to park on the narrow roads I mow on. The Ranger pulls the load good as long as I don't try to use overdrive.
Ford F350 & Ranger
Exmark Lazer AS 60" 28hp Kawasaki
John Deere GS30, 14PZ & WE85 Gone Gone Gone
Honda HRC 216
Shindaiwa T270, M231 Muliti-Tool & EB802
Stihl MS230 CBE