[dsraven]

another thing you can do is get the suspension down so the lower control arms are level to the ground (the normal ride height for the original unit the frame came from) and use threaded rod or another solid link type to capture the suspension in that position. remove the shocks and use threaded rod or square tubing etc in their spot. that way the ride height will be the same throughout the whole build until the rods are taken out. at that point you can drive it a bit and then adjust the springs after they are "broken in"
when I started my frame swap I first "pinned" the suspension on all 4 corners on the donor vehicle before the body or driveline was taken out. that way the suspension will be where it was engineered to be at ride height. when I am done the frame swap I will remove the links (square tubing in place of the shocks) and adjust the suspension with the total weight of the "new" vehicle sitting on the frame. the completed version will have full suspension travel like the original vehicle had instead of more "up" than 'down" travel depending on the weight of the new vehicle. wheel alignment will be easier because at ride height the suspension is sitting where it was engineered to be.
speaking of alignment, ensure the alignment on the donor frame is sorta right before you go setting the cab down and fabbing mounts. like alluded to earlier in the posts, the design of the suspension can move the axle center line forward or back as the suspension travels up and down. alignment adjustments can do the same thing. if you started out with an s10 frame that was not in an accident and was pretty close to being in alignment then you are prolly ok. a frame that was in an accident could require some tweeking and the axle centerline could be affected. better to find that out before doing a bunch of work on cab/fender placement. rake angle wanted compared to original rake angle intended for the donor frame can also affect the alignment. all good stuff to figure out before cab mounts.