If you want good gas mileage I would try to find a Dodge Ram Quad Cab with the 3.7L V6. I get around 22mpg with that thing just driving to work and back and about 26mpg on the highway. The 1500 dodge has bigger diameter axle shafts than a Dana 60 and good brakes.
After the dodge I would go with a 3/4 ton chevy or ford. The half ton chevy and fords are junk, they have really weak axles and are built cheaply.