My 2011 6.2 averages 15+ mpg unloaded and rides great. A 2500 does not ride great. My 2007 6.0 was about the same. A heavy duty suspension does nothing for you while trailering a jeep that is set up right. An equalizer hitch is a plus. I wouldn't worry too much about brakes unless you are towing a bunch, which you are not.
For the miles you are talking about, do the math and I doubt you can justify the diesel.