Our 1 Ton F350 Dually is not exactly a luxury ride! To help improve things (even just a little), we made 3 mods to the truck:
Airbags - We had the Air LIft 7500XL with the AIR LIFT 72000 Wireless Air Leveling Compressor installed. This takes some of the force off the springs and shocks. Helper Spring Stop Removal - Once we had the airbags, we really no longer need the helper springs. But removing them or replacing the leaf springs is a pain. So, I just removed the stops for the helper springs. Sulastic Shackles - These put a rubber shock in between your leaf spring and frame to help dampen the forces between the springs and truck.
These three things definitely help some. But, it's still a rough ride compared to any normal vehicle.
If we were made of money, we would get a full air suspension replacement installed. Something like Keldemann.