You're right, my 04 4wd, 6 cylinder, 5-speed manual averaged 15... 14 in Winter and 16 in Summer. Two years ago I gave it to my son with 90,000 miles on it and it still drove like new not squeak and still with the original brake pads. I did nothing to that truck other than change the fluids regularly myself. Ridgeline is a better truck for how I use it and gets 20-21 mpg in the same type driving. I do miss the manual transmission sometimes though.
I still maintain if one wants a full size truck and they plan on keeping it for 100,000+ miles a Tundra might make sense because the extra gasoline it uses will likely be offset by not having repairs along with good resale. Personally I wouldn't even consider buying a used truck with over 100,000 miles that had a turbo gasoline engine.