diesel is the answer to your problems...do your research and take your pick, ford chevy, dodge. they all get pretty good fuel economy towing, it depends on what year you go with and so on. lots of research is the key, but diesels are reliable, they do get better fuel economy when everything is working properly, especially 2wd trucks. my dads 95 dodge ram 2500 5spd manual cummins diesel has been getting about 20-24mpg towing since 2000 when he bought it with 60,000 miles, and now 12 years later he's at 270,000 and he's had some work done to it so it has more power, about double what it started out with, and it even with 300-350whp it still gets the same mileage if its driven easy. back in 2011 when i bought my 96 f350 4x4 automatic 7.3 powerstroke with 4.10 gears i was getting 19.8 mpg towing 6000lbs all highway. for 3 hours. then around town with a dual axle 16' dual axle landscape trailer and about 2000lbs of equipment i was getting combined 16mpg stock with 240,000 miles.