We sailed at Halloween a couple years ago. Our kids were 4, 2 and 7 months. Halloween was actually on our Castaway Day so the festivities were the day before on the 30th. My kids were really little, so Halloween wasn't a huge thing for them, which was good because it was very disappointing. The had a Treasure hunt for candy. You followed the map to different locations for candy. It was so crowded and so unorganized. They hardly got any candy. It really wasn't worth the pushing and shoving for what they got. If the kids had been older I'm sure they would have been more dissappointed. We ended up giving up on the treasure hunt and going to the pool which was empty at the time. That was great! In the evening there was a big costume contest. That was really neat. The costumes were pretty amazing! Some families got right into it and were even handing out treats as we were going into dinner. That was very nice of them!
To sum up, I wouldn't do a cruise for Halloween with the kids until they are out of the trick or treating excitement, but I thought it was neat for older kids and adults.
Lisa