Used Roadmaster Active Suspension. Roughly 12-15k on them, set to the lower white shim.
Really improved the ride with the added load of the Decked box and the Ladder rack. only issue I had was my day to day materials needs changed so much, so I ended up getting air bags.
If you have added weight to your bed and want to get back to stock ride height with the feeling of a progressive rate spring this is the tool for the job.