Just one thought on the dually versus SRW.
If you live in an area that gets a lot of snow, you will not like driving a 2wd dually.

I had a 97 3500 Ram diesel, and in the snow it was a handful as the front tires and the rear duals do not run in the same track. In heavy, wet snow, the rear is always trying to jump from one rut to another. Luckily, mine was 4WD, shifting into 4wd and the truck was stable as a rock.
One other thing, when a dually is in 2wd and the bed is unloaded or lightly loaded, they will get stuck on level wet grass.

I never liked the way my 3500 Ram rode, but, after changing over to Rancho 9000 adjustable shocks and stiffening up the front and softening the rear it made a huge improvement in the unloaded ride. I also bought a set of E-Z Ride shackles from 4 WheelParts (can't remember who they are made by) and they not only leveled the ride height of the truck, but with the shock change, it rode better than the Durango I traded it for in 2000.

I've got a 01 2500 extended cab shortbed now, and it rides quite well, except when pulling the 8K pound tag along camper on PA roads. But then, not much rides well on PA Interstates....