As long as the trailer brakes are up to par, and everything on the truck functions like it should, I don't see any reason you should have any problems towing your Duster with a SWB Dodge. Lots of these trucks towed lots of stuff for a lot of years. A step up in shocks & springs helps everything.

That said, the long wheel base does add to stability, and helps reduce the feeling of the tail wagging the dog that can occur when the truck weight and trailer & load weight near each other. A 3/4 ton adds even more stability, because of the extra truck weight, bigger brakes & heavier springs. I've probably towed trailers over 100,000 miles without the need of rear sway bars on my trucks. Figure out how to properly load the trailer. They probably help, but i never felt a need for them.

A 318 with 3:21 or 3:55 gears has enough power to get you moving and keep you moving along, but don't be fooled into thinking only the truck brakes are enough, you also need functioning trailer brakes. Add a big trans cooler. Gene