Decisions....Gas or Diesel

Wife & I upgraded our travel trailer camper this past year... Its 34.5 ft overall...6820 dry weight... & probably at least another 1000 lbs by the time you get everything in it to camp for 2-4 weeks at a time? Now we are going to upgrade the tow vehicle as well... Looking at Ram 2500s... Now the decisions... Gas or Diesel??? They both have their Pros & Cons...6.4 Hemi is 420 HP... 6.7 Diesel is 380 HP. I know that the diesel probably has more torque on the hills...plus Jake Brake on some models. Does anyone know what these get for mileage? Both empty & pulling a load? Figure i can buy a lot of gas for the difference in cost of the engines & at the pump??? Thanks for any & all advice!!!!