My best mileage around town to work is 17. The best I've had on road (285 mi. One way) is 19.8. Use the cruise and keep your foot out of it. I tow my 8000 lb. Bobcat 200 miles (road) and get 13.2 nothing to complain about. My p/u only got 10. I will buy another Avalanche. I drive it like it's my Caddy and I'm 64.
The first time I opened the midgate I was amazed at how big it was (take the window out ). No wheel wells to catch little junk.