I just finished up a little trip to the Smoky Mountains. 2015 CG Laredo 2X4, V-6. 459 miles on a tank and it was about 150 miles interstate and then we went around through NC. The Cherokee National Forest, Cherohala Skyway and even the Tail of the Dragon. Lots of backroads and mountain driving. Ended up getting 22.7 mpg on that tank.
On the way home, I filled up just before getting on the interstate. Drove 162 miles at around 72-74 mph and then filled back up when I got off the interstate. Only got 23.9 mpg. I'm very happy with the overall mpg, but a little disappointed with the interstate part. I thought it would be better.
Mileage was figured by dividing gallons pumped into miles driven. Not by the little thing on the dash that supposedly tells you how many mpg you are getting.