I think the Ram 1500 with 3.6 v6 and 2wd is rated for 25 hwy (a few mpg lower for the 4wd). Though it's been my experience that the EPA's mpg ratings for gasoline rigs are overly optimistic....meaning you might see 25 mpg when a lot of if's are met: if you are empty, driving below 65mph, on flat terrain, no traffic, no head wind, no accelerations, ect.
My 4runner is rated for 22 mpg hwy, but realistically, I'm lucky to break 20 mpg (I've seen 22mpg on the rare occasion, but it certainly isn't the norm even on hwy). I wouldn't be surprised if real world results turned out to be somewhat lower than the EPA's ratings for the Ram as well. The extra gearing in the transmissions help, but you put these gasoline engines under any kind of load and the mpg's start to take a dive.
I think the only way gasoline truck engines of the future will break 30mpg (with consistency) is by going the hybrid route, or they could build a hugely under-powered engine and put it in a super low-riding truck with all kinds of air dams and focus totally on fuel efficiency to the exclusion of any sort of towing or offroad utility....but where is the fun in that?
Me, I'm resigned to the fact that a gasoline SUV or pickup will never be as fuel efficient as I want it to be, and in the near future I'll likely be buying a diesel truck (I'm looking forward to seeing what Ford does with the new Ranger and F-150 V6 powerstroke). Despite that one gripe, I can't really complain too much about a well-made gasoline truck engine. The 4.0l v6 in my 4runner is endearingly reliable and dead-nuts simple (relatively speaking) to maintain. 10k oil changes, change out the air filter when it gets dirty, I'll likely do a radiator flush at 80-90k, and the thing just starts and runs, irrespective of the weather conditions or the hard driving I subject it to. A modern 3/4 ton diesel engine will get nearly the same mpg's as my 4.0l v6 all while providing much higher torque, but they're so much more complex by comparison....everything's a tradeoff I suppose.
