On our 2006 F350 DRW LB, we've used quite a few suspension modifications. Here are my thoughts, FWIW:
With the camper (OK 117DBL), we had Firestone bags installed with camper install IN Sieverville, TN. A bit of roll, but manageable. Truck did sit a bit low in back with camper on. A few short trips things were fine, but after a long trip to AZ, the bags failed (caught the mounting bolts and ruptured due to poor install...).
When I got it home, the RV repair shop recommended a spring shop to look at the issue, and the owner suggested I skip replacement bags and look at "Extreme Service" Timbrens (that was the name then, I assume it's different now). Much less roll, more stability, and we used these until 2016 or so.
Along the same time, I added bigger "bump stops" for the overloads. I think I followed some advice on here and used Energy Suspension blocks, though I know some used hockey pucks or other items. That helped as well.
IN 2008, I added Hellwig overloads (I think, they are a spring with a hump in the middle to mount over the existing spring pack". I removed the Energy Suspension mods and that helped, mainly because the existing spring pack was losing some of it's capability.
We quit using the camper as much in 2011, so the existing solution worked fine until 2016. At that point, the suspension was needing some more drastic attention, and so I swapped out all four points for a Kelderman Air Ride.
I've always wanted an air ride with auto levelers, and I like it for our use, but it's a very expensive option and it's not for the non committed. You literally take all the suspension off your truck and replace, so it's not easily removed. I know many that have a fondness for bags, but even the air ride system has a bit more sway than I would prefer, but the Firestone air bags were even more so, in my opinion.
I did not try the overload helpers like Torklift and others offer, so I can't comment on them, but I think the Timbrens are a awesome investment, because they are easy to add and remove, and they only engage under load. That helped keep the lights where they needed to be at all times.
The Kelderman would probably be on the bottom of my recommendation list, mainly because it's expensive, has more roll than Timbrens or springs, and is probably more prone to issues due to the mechanicals and the air system. That said, it's an impressively cool system, and the auto-leveling system with the rear dump (lower the bed) option provides tons of truck cred :-). Boys and their toys, you know...
Jim
