Richard, you need to find a good used diesel. One that hasn't been used commercially. I would go with a Dodge or a Ford. Most gas trucks are guzzlers when towing. This is why the trucking industry primarily runs diesels. Diesels will run good for 300,000 miles so you probably will be safe buying a truck with 100,000 miles plus on it. I love the Dodge Cummings diesel trucks, 1990 to 1995. Good transmissions. 5 speed would be nice. 3/4 ton. Yea they are expensive when repairs are need but if you take good care of them, you won't have many repairs ie change the fuel filter and air filters on time. Put in a diesel fuel additive on a regular basis to clean and lubricate the injectors.
My advice is a bit too late now that you just bought a truck. Everybody needs a back up truck LOL I am looking for a back up truck whenever I get the money to buy one