Keeping with the Snipe remarks, my 5er has a "Hot" water heater....
I checked with other Ram owners at work, and the general consensus is 500 to 700 miles to the gallon when towing. The Chevy guys report a little better.
As for the advantages of DEF, I only mentioned "Gas" mileage (input snipe here) in my earlier post. The DEF utilizing Rams also go twice as long between oil changes, with downside being the truck doesn't "make oil", so I'm now not recycling as much, and hence not doing my part for the environment. Fuel dilution due to Re-gen blow by and excess carbon build up from high EGR was fairly significant on my 2011.