I get about 14 daily driving with my '11 4x4 Limited Tundra. If I baby it I have seen 16. Towing boat = 10-11. Towing 31.5' 8500lb camper on turnpike at 70mph = 5-8mpg
Truck has all the power I could ever use even going uphill with 8500lb camper at highway speeds.
I have lots of miles on it towing boat, camper, tractor and racecar.
With 100k+ on the clock, it has been problem free. (unlike many co-workers with newer GM trucks)