I am considering a Ram 1500 4x4 with 3.0 diesel. Most driving (90% +) will be general use, mostly highway. Some towing will involve my trailer that weighs about 5K lbs with maximum loaded weight 7K lbs and hitch weight 550 lbs. Is the 3.0 diesel a good option? What mpg has been your experience towing and without tow for the 3.0 diesel? What year, model and options should I get? Thanks in advance!