I just did a trip from Williston to Perrault Falls Ontaio, about 650 miles each way, so 1300 total....the average for the whole trip was 11.7 mpg. That was flat, hills, calm, wind etc etc. 2016 3.5L EcoBoost towing a 21' Alumacraft with 250 and kicker, travel cover. I was pleased with that.