[SCOTI]

Bushings are likely toast if it's been used & not a yard queen (the last Square trucks built are 40yrs old now). inspect them & plan accordingly. Your plan for the front seems good & you're correct the shock travel won't change w/the spindle swap.

For the rear, same rules apply for the leaf bushings. I would opt for relocating the lower shock mounting point w/shock extension brackets to get a better angle on the shocks & to allow using stock spec replacement shocks vs. 'drop' shocks.

When you get it aligned, the 'book' will call for +.5 Camber. Request 0 (zero) to -.5 Camber & as much Caster as they can dial in w/that new Camber set-point. The lower center of gravity & updated camber spec will be an improvement.

Check the other steering parts while you're in there. The tie-rod ends, Idler, & Pitman arms need to be in good shape as well. Summit Racing offers the Moog product line & they're usually 50% less than your local parts place on the price.