I replaced them before when doing the conversion to power disk brakes and everything had to come off anyhow becuase I wanted new ball joints and bushings installed. Now that I have a big block it was obvious that I need the correct springs so I'm doing it again. But this time I only want to remove what is necessary, can I leave the brake rotor and caliper connected? After removing the shock and compressing the spring can I simply loosen the top castle nut and break the spindle loose with a pickle fork? Thanks.

Leave the brake stuff on. Place a chain to keep the spring from flying out. Safety is a must. Compress the bottom arm/spring. Loosen the bottom spindle nut a couple of turns, do not remove. Release the compression, but keep the jack under the arm. Whack the spindle with a small sledge hammer. That should pop the ball joint out. Recompress the spring. Remove the nut. lower the arm. Remove the spring.
Should take about 30-45 minutes each side.
Also note the BB springs may need a spring compressor to install properly.

I had one problem doing that way. The outer edge of the LCA hung up inside the slot of the backing plate which kept it from dropping out of the way. I finally managed to do it but be forwarned.