I just returned from a 700 mile trip (Birmingham, AL to Gulf Shores, AL) in my Ram. First tank had a lot of around town driving on it as well as 75 mph interstate driving for 200+ miles; it came to 23.3 mpg
measured, 23.8 displayed over 457 miles. However, I filled up before coming home and I took a different route. It involved more stop and go, and more hills that required downshifting from 8th to 7th and occasionally 6th, but lower overall speeds (the highest limit is 55mph; I averaged 62 on these stretches with cruise control). When I pulled in my driveway last night, I'd driven 262.3 miles over 5 hours and 10 minutes. My average mpg was displayed at 27.0 MPG
Regardless of whether or not this is off by as much as 1 MPG, I'm still pretty happy with this for a crew cab truck loaded with 500 lbs of passengers and gear.