Stop in for a cup of coffee

My RAM 1500 will do 22 in the flatlands unloaded. Throw in a few mountain passes which are common in Ca and it drops to 18. Here to Phx is usually right at 20 for the entire trip.
IF I set the cruise control on 60 MPH, might get 15MPG. I have a friend who has basically the same truck, with Smog crap deleted, He is an Native American, living on the reservation. He is exempt from "white mans laws" His words. 28 MPG all day long. And no issues. He told me he got 32 going normal speeds!!