Too early to tell yet what my mpg will be towing. I have only gone about 40 miles with it so far. I got 15-16 mpg going to Erie steelhead fishing in early March. That was 4 people in the cab and the bed full of gear and food. Running around daily driving I get 11-12 mpg with the cold weather gas. Last fall I got around 13 mpg before they switched the gas for winter. I am expecting in the 8-10 range towing if I keep the speed around 60 mph. I would have loved the Duramax but the wallet would not have.
TV - 2011 Chevy 2500hd CC SB 4x4 6.0l
TT- 2012 Jay Flight 32bhds- Elite, Thermal, Technology, Hide a Bed, Outdoor Kitchen, Ladder, Power Awning