We just bought a new 4 door 1-ton Dodge dually diesel in May. We looked at regular cabs but, ruled them out because I like to be able to sometimes recline. Plus, it's nice to have the back seats on the rare occasion that the kids go with us. And of course we had to think of our future grandkids (far far far future
). I recommend that you go sit in one, take it for a test spin before deciding.
P.S. Our old truck was a Cummins, 1996. It pulled our 36' Jayco over the Rocky Mountains at a steady 70 miles an hour. Took it all the way to Arizona, Nevada, California, Wyoming, South Dakota and then back home. Got pretty decent milage too.