I know this goes against the grain but I've had a 4x4 tow rig since 2003 and as of 2009 had used 4x4 on 3 occasions. When trade in time came I specifically looked for 2wd truck becasue: they were cheaper, ride better, have less maintenance, are easier to get in and out of and 2wd dually looks better (I think).
I have had no regrets and never looked back. To those that don't agree with the "as long as you think about where your driving your OK" comment because you can get stuck before you know it. Well; you probably have a 4wd and don't have to be aware of where you are driving so yes, you get stuck before you know it and require 4wd.
My point is, it's just like wheeln'. If you're by yourself, don't go where you don't think you can go. If there are doubts and you have another vehicle with you willing and capable of pulling you out then go for it.
Yes I have been stuck once (in the back yard) but got the Toy and pulled myself out. If they're calling for rain and you leave your trailer in the back of your lot as I do, then pull it out a few days ahead of time. The Dodge actually performs very well in the snow but again, you need to know your limits.
If you initially wanted a diesel and doubted 4wd vs 2wd then I would stick with the diesel. Wether the gasser pulls great or not you will be dissapointed cause you didn't go with what you wanted....especially after you owned the truck for a year and have never put it in 4wd.