I'm really late here... but this is how I would plan to do this...
Most has been said already...
You MUST find a level place to work on the car with a solid enough surface to support your jack stands (asphalt does NOT count)...
Parts list... U bolts, center bolts(if reusing old springs) flex hose for the rear brakes and shackles if available... I would avoid reusing U bolts... I bet a local truck spring shop can still make you new ones on the spot if necessary, they may have serviceable center bolts on hand too..
My preferred penetrating oil is ATF... soak everything thoroughly at least once the day before, and a "wire tooth brush" is a good way to clean the threads before you start (but lots of work if you want to risk a wire wheel, face shield advised).
Disconnect the drive shaft, the brake hose (cut if replacement is ready), you may not damage the steel lines if you're careful. loosen everything while on the car... if you do it ahead of time you should find out what's going to break. Lower the rear of the springs first, use a floor jack under the diff until both sides are free, unbolt the front hangers and roll the axle assembly out on the tires.
Swap the springs behind the car where you have lots of room, and roll back under... connect the front first, then the floor jack to raise and connect the rear. New brake hose and bleed brakes (if you pinch whats left of the old hose while still attached to the front line, this will go easier)... chances are you will damage an old hose fooling around anyhow... so just go for it.
Every bolt and bushing has potential to be rusted in place or snap off... the more you are prepared to deal with that the better. Lots of "incorrect" fasteners are available, be careful of grading if you go there (grade 8, not 5). If stuff fights you, be careful to sacrifice only the parts you can get... like drilling a bolt to death to save a front spring mount (been there, done that).
I know west coast is supposed to be better, but if your car spent time at the beach, you might still have rust frozen stuff due to minimal corrosion protection on these parts.
