I went on an Alaska cruise about 1 year after being diagnosed with right arm CRPS. I had no issues with the cruise- plenty of opportunity for rest and relaxation. I wore a large thin jacket to protect my arm from the breeze (I usually can't wear anything on my arm). My only issue was the 4hour time change really affected me and took me about 4 days to recover from.

I would do a cruise again if it didn't have such a large time change. Or I'd arrive a few days early to adjust to the time change.

The motion of the boat didn't affect my CRPS at all and I slept like a baby at night.