its really too tuff to say what kind of mileage to expect. it really just depends on what you do. my 2011 6,7 ford would probably be around 15 mpg in the city. if I run it at 70 mph constant down the freeway I am sure I could brake 20 mpg, but I never drive that slow, so running 80+ I am around 17 mpg. but if I am running winter fuel plan on about 1 mpg less.
speaking of cummins this ford gets better mileage than all but one of the dodges I have owned or driven and that was a single cab 2wd 93 model that would normally get at least 20mpg with some city and highway mixed. best was 23 mpg on a leg through the mountains on the way to texas, I would always get 23 on that part of the trip for some reason, happened several times. I have spent time driving 6 dodges either I owned or my dad. people claiming in excess of 20 mpg with a 4wd model are either keeping the speeds below 70 or they are lying and or don't know what they are talking about. the 07-13 dodges with 6.7 and no DEF system get terrible mileage honestly they aren't a whole lot better than a big block gasser that motor is chocked something terrible with EGR. dodge was to cheap to upgrade to DEF/SCR technolgy until now.
