Were you driving the truck prior to taking it off the road? The behavior on the road might inform some of your decisions. Some will say, if it was not broke dont change, with the corollary of, first, do no harm.
With that being said, I would recommend (at this point) replace all of the suspension bushings since you are there. Get the frame back to rolling chassis. I dont think there is any preferred sequence, front or back. Ball joints may be easier to change from your bench if you decide to go that route.
Springs - inspect and reuse, but they are not hard to find and replace if budget allows. The spring cups will be rusted and should be replaced. Look for cracks and welds on the springs in case they were damaged in the past.
Ball joints inspect and replace if needed. Some will say just change the ball joints so you never have to worry about them. I did not change mine. It has not bit me yet, but I think there will be a day when I wished I had changed them when I had easy access.
Steering - inspect. Steering gear, pitman, connecting rod, and idler arm are likely good to reuse. Tie rods and tie rods ends are cheap and easy and replacement now will make alignment adjustment easier. Spin steering gear at the spline. It should spin freely and not hang up anywhere. If it spins nice, clean exterior and check grease level. If it looks all cruded up (in that the seals were leaking) or if it does not spin nice, rebuild with new seals and bearings on your bench. Good description in the shop manual and on line.
Brake lines, brake components, parking brake.
That should keep you busy for some time.
