2015, Ram 3500, SRW, 4x4, short bed, mega cab, 6.4 gas. With 5000 lbs of extra weight from camper and goodies it gets 8.5-10.5 mpg. Empty 13-15 mpg. With the massive amount of torque and HP of the new diesel trucks you cannot make the diesel pay for itself due to increase in fuel economy, and if al you plan to do is haul a slide in camper the gasser is more than enough to get the job done. With that said, when you are running up long steep mountain grades be prepared for that gasser to gear down and the rpms to come up to 3500-5000 rpm to maintain speed.