Bushings will help, marginally. I want the same thing, but you have to keep in mind these trucks will never steer or feel like a BMW etc. :-(
check all your tie rod ends, idler arm, drop link for starters. replace if they feel lose at all. LCA, UCA bushings, radius rod bushings, upper, lower ball joints should all be checked.
Adjust the backlash in the steering box. My 90 has manual steering and it was a bit loose when I got it. I took about half a turn to snug it up and now it's perfect. A word of caution though if you go too far you'll lose return to enter and the steering will be difficult. I have urethane bushings going in soon to make it even better.
sign of a worn gearbox. Mine's bad too. It tightens up the middle section but not the outer 2/3. Not really fixing it and only half the adjustment. DON'T OVERTIGHTEN it or you'll really chew up the gears and bearings.
Hold the center adjuster screw while you back the lock nut off a turn or three. Then turn the adjuster screw in a little at a time and wiggle the steering wheel back and forth a bit to get the sector shaft seated in it's new position. Then adjust a bit as necessary. Once you've turned it in enough there will be no slop but the steering will still be easy to turn. If you go too far there will be no slack but the steering will also be hard to turn.
I think I am going to swap to power rack soon I have setup in mid that should work just have to swap the alt to were the ac is so it's easyer to run steering linkage