The other day, i had to drive from Cincy to Cleveland...reset the monitor as i got on the highway. With a light foot, cruise control the entire way, and a pretty serious tailwind, i averaged greater than 26 MPG. Also, Cincy to CLE is relatively flat.
On the way back, I duplicated the exercise and got about 22-23 mpg.
So...20+ mpg can definitely be done...
EDIT: forgot to mention, i am stock sahara tires, rims, and suspension...only difference is Rampage Recovery front bumper.