My memory of those trucks seems to be different from most of you. The 2wd square bodies were usually pretty smooth riding. I cannot remember how many times in the '80s I heard someone say, "This truck rides like a car!" Of course the top of the line trucks came with white wall "car" tires.
It looks to me as though your tire choice is not helping you. They may look cool but if they are aired up to max pressure, they are going to be stiff.
@Grit dog and I are in agreement on this.
I would try replacing the front coils with a new set as close as I could get to the OE spec. The leaf pack in the rear rode pretty smooth in its day. You can affect the ride quality front and rear with the right shocks also. When that truck was new a set of Monroe Gas Magnum shocks would really make the ride stiff but they helped it handle better on a curvy road. The factory shocks were usually shot after 30K miles or less.