I drove from Jacksonville to Pensacola and back this weekend. One way it is roughly 5 hours.
With the cruise control set on 85, 2 kids, wife and luggage, was getting an average 13.9 to 14.4 on the highway.
We met up with my parents 1/2 way and I drafted him for the rest of the trip (05 yukon denali xl). I reset my average economy thingy and was getting 15.9 to 16.2 going 85.
4:10 not too good on gas but great for passing