That's great mileage! I rarely get over 10 mpg with my 2020 3500 truck, and my last rig was a 2500 cummins and a 13k Jayco Eagle; it was about 9mpg average over a long trip. But, we almost always have mountains as part of where we go.
What terrain were you hauling on? And, what distance was this over? Any mods to the truck?
Sorry for all the questions, but if you can regularly get that mileage towing a Pinnacle, I want to know more!
Thanks in advance,
Brad