Moving up 1/2 to 3/4 ton

Towing our Jayco HT 26.5 RLS and our 19' Crestliner, we get around 12 mpg and just got back from about a 350 mile round trip with just our boat and got about 14 mpg. Last spring we took a 3,800 mile trip, about 3,500 towing the FW and averaged 11.9 mpg for the whole trip, to Idaho, Nevada, California and back up through Utah to Wyoming. When driving 70 unloaded we have gotten anywhere from 17-19 mpg on the highway. Now, this pales in comparison to our hybrid which gets 35-40 consistently driving 70 and 35 consistently when driving on the interstates at 75-80. Our DA combo crew-cab weighs around 8,000 pounds fully fueled and ready to go. The D/A combo gets about 40% better mileage in town and about 50% better mileage towing than did our old 454 Vortex back in 2002 before we sold it to get out first diesel, we're now on our third after the middle one, a 2011 Dodge 2500 with a six-speed manual turned out not to be the bet choice for us, after nine months of ownership, for various reasons.

Having said all that, I would hazard a guess that your towing mileage will be less than 10 but unloaded you will get closer to 18-19 on the highway and 12-14 in town.