Gien the weights involved I would go this way..And it is a given that tuning a suspension involves some guesstimatation so here we go..
On the steering box i would order a repalcement item from borgeson and ditch the rack and pinion..I know I know the rack and pinion is the fad of the moment and in fact workss fine with a suspension designed from the get go for rack and pinion..but yours was not..you can get several different ratios including some fast steer boxes suitable for autocross or road course and of course I would have power steering.
Spring rates i would run a 350# spring up front and about a 150# rear..Ladder bars would be good but mount them close together up front like a modified truck arm..aftermarket sway bars make the front one fixed rate and the rear one adjustable rate in order to help tune the oversteer/understeer character of the car..On your truck I would plan a pair of auxillary air bags just in the event that you need to haul something.
Most of all get yourself some good books like Tune to Win by Carroll Smith and there are several good ones from Steve Smith Autosports that go into depth on suspension tuning..Most of those are for the circle track guys but if you can tune it to turn left then you cam balance the car to go right as well..one just forgets the special circle track stuff such as wedge in that case..
In any case take a hard look at the primary use of the vehicle and plan accordingly..
I have tried most all of it and now do what is known to work..