You'll love your new Dodge, I have a 2010 Ram 2500 Crew Cab Big Horn Package with Cummins Diesel, initially pulled a travel trailer behind a 2006 Dodge Durango with Hemi. It had enough power but was actually overloaded with the travel trailer we had and the Hemi only got around 6 mpg when towing and did not really feel too stabile-comfortable pulling with it. Behind the 2010 Ram hardly knew the trailer was hooked on lots of power and stability and got around 12-13 mpg towing the travel trailer.
We since have upgraded to a 40' fifth wheel and mileage runs from 9-11 mpg depending on pulling conditions, but I run speed limit or slightly above and it is REALLY STABILE, and pulls nicely. On hill grades North of Branson on 65 the biggest longest grade, speed went down to around 50 mph or just over, but diesel leveled off there and rpm hardly changed (from a truck driver friend appears the Cummins does that on big grades).
I also love the Jake Brakes, & I believe in the 2010 Ram 2500 and since they increased the brake size, and up the supension. I know it handles very well.
Plus in playing around you mpg will increase 2-4 mpg if you slow down and don't run like I do down the road (55-60 mph gets a lot better mpg than the 70 + mph).
2010 Dodge Ram QC 2500 HD w/Cummins Diesel
2013 Salem Hemisphere Lite 346 QBUD