Before investing in a 3/4 ton truck for occasional trailer towing and everyday driving I would take a long hard look at the new Ford F-150 with the 5.0L V-8 engine and its optional 36 gallon fuel tank and optional 17" pr 18" wheels.
With a WD hitch and sway control bars it should have no difficult towing your trailer and hauling your family members and all your gear.
You will have at most a 7,200 lb. tow load and to get a 2500 truck with a 17,000 lb. towing capacity is truly overkill. You will have a harsher ride and can expect to pay 50% more for fuel for no real world advantage.
It will help a great deal to get the truck with the lowest gears offered by the manufacturer for the model with the gas engine. With Ford it is going to be 3.73 gears. Higher gears help with EPA statistics which is important to Ford and the CAFE standards it has to meet but will hurt towing performance and not likely to make a significant difference in everyday fuel economy.
The big three all have to meet CAFE average fleet fuel economy standards set by the federal government and trucks drag down their averages but also are the most profitable vehicles they sell. They have done to transmissions with more speeds and to using ultra high gears to improve the EPA test results which are not conducted in a real world driving situation, which is why seldom does anyone actually get these results with their own vehicles.