I have an 06. Had an 01 and 02. The newer trucks get worse mileage than the earlier trucks. These high mpg guys are either going by the lie o meter or live in areas with no hills.
My truck will get 14 to 15 around here. On the high way about 20 mpg. Towing 12,000 lbs about 11-12 mpg.
My son has the 02. The truck gets 18 around our area but it is also a stick. On the highway he gets about 22 mpg.
Don't expect a new truck to even get these numbers. Expect 12 around town maybe 19 highway empty and 11 towing. If you get more great but dont expect it.