Not pulling a trailer but the aerodynamics of my truck camper means pushing a barn door through the air. I have a 2013 6.2 DRW CC with 4.3 rear end. I got the gas in part because I carry a 5,000lb+ truck camper and the diesel losses almost 1,000 lbs of payload capacity. (My yellow payload sticker reads 6,200+ lbs :) and I have lots of options in Lariat trim)
Truck has been up and down mountains in the west (Beartooth, Big Horns, etc) and the engine and transmission have been a great combination. Average a little under 9 mpg with the camper. Had to order though as finding gas DRW in anything other than white XL trim was impossible.