I have an 08 ram 1500. City I'm avg about 13-14 and highway avg 17-19. Towing a 21ft north river gets me about 10-12 depending in where I'm going. The last few days I've been driving a buddies 06 3500 cummins and that thing is avg 20mpg!!! If I didn't have a lifetime power train I'd be finding one of those in a heart beat.
I also had an 08 hemi half ton and it was a great truck for me, and I got the same milages as mentioned above. Until u put Ur foot in it then you will drop to 10 mpg. The only reason I got rid of it was to drag around a bigger rv so I got an 05 cummins, and I will never go back