Air ride is the way to go, but it isn't cheap. Kelderman makes a hybrid sort of system for less, will help with the unloaded ride but not the loaded ride. I'm not sure a new truck is the answer either. My '15 Ford DRW rode rougher than the '99 it replaced. There are better reports on the redesigned '17, but I have no first hand knowledge.
I put air suspension on the back of my '15, it is a noticeable improvement both empty and loaded - more so loaded, but still short of a Cadillac ride. After a year, I feel it was well worth the money for me (around $4K self installed).