Sorry i've not gotten back to the post since the original message but I've been out and about in Montana for quite some time.
In the mean time I've added a custom spring into my existing spring pac through a local spring shop that specializes in this sort of thing. I had a few choices which included a new spring pac for a dually of the same year, or a single spring inserted into my existing. Each one of my springs added 440 lbs capacity or 880 total. My camper, the Hawk camper must weigh at least that amount I thought so I went ahead with it. The difference is amazing, no more sway/roll and the ride seems either no different or perhaps better as I'm not getting the bouncy heavily loaded spring feedback into the cab.
Some stats here:
Before new spring the front end was 1" lower than the rear as a stock set up.
With the new spring with the camper on it is now idecntical, so the spring choice was spot on.
Withe the new springs and camper off I'm 2.5" higher in the back vs. the front. So the new spring added 1.5" of lift in the rear.
So driving down twisties and around pavers of all sorts the truck is MUCH more stable and predictable at all speeds.
However off road is suck ass really bad. I bottom out the front end quite easily and the front end seems not matched to the rear from an articulation perspective, unbalanced so to speak.
I spoke with Don Thuren about this and we came to the conclusion that his 2" soft coil would be ideal. So I've ordered them along with a new Thuren trackbar and new sway bar end links and we'll see how that goes. I put new bushings in my stock swaybar but they allow 1/4" of movement, or worse than the stock bushings. I got mine from Gino's garage and they are red in color. Hence the new trackbar.
My hope is that the front end will only sit an 1" higher than the back, I'll pick up a better ride, and the truck will offroad more effectively allowing for less front end roll/sway together with the new trackbar. And if I ever take the camper off the truck will be balanced with a couple inches only of lift.
In doing what I've done with the suspension, it is still basically stock but enhanced a bit. New Red Hat steering box, steering box stabilizer, Dynatrac Ball Joints, New T-Style dragbar, new stabilizer shock, and Bilstein shocks. I don't view the 2" increase in lift via a coil a huge suspension mod, it just help keeps the frame/bumpstops off the axle when off road so I'm not at a crawl over the smallest dip , washout, or water diversion hump. Turns out that Diesel front end is heavier than I thought.
As mentioned though having owned a Nissan Frontier with a Finch on it, all the same things need to be done to any truck imo. I'm happy to have the pulling capability of the diesel, more room in the vehicle and better fuel economy than the little gasser. I'm averaging 16 mpg with the camper on. 13 with the camper on towing two motorcycles on a flatbed aluminum trailer, and over 20 naked. I drive 69 mph on the slabs or just under 2,000 rpm, this seems to be the sweet spot for mpg.
As a sidenote, with or without the camper on the front end distance from wheel well to ground is unchanged, so it would appear that all of the weight in the bed of the truck is being managed by the rear end, probably why the spring upgrade back there made a HUGE difference. But the front end is affected by the top heavy weight of the camper when you 2wheel or go around corners, you can feel the front end sag in a sharp corner much more than the rear. Hence the front end upgrade to the springs.