fwiw.... any tire shop with a clue about liability will not install anything that de-rates the truck.
You can play around with shocks and tires but nothing will really make that much of a difference with a 3/4 ton truck. If you really want a soft ride like in a 1/2 or passenger car get air suspension.
My buddy's 2500 came with that and it was amazing. The thing rode like a Cadillac. If/when you need to haul some weight you just push a button on the dash and pump it up.
The 2014 Dodge trucks are coming out with this for the rear end and it should make a big difference. The harsh ride on 3/4 ton trucks is just a fact of life. You can't have a suspension capable of carrying a lot of weight and have a smooth ride at the same time.