I was on the same cruise.
Castaway Cay was a disappointment due ot the rain. All excursions that day were canceled. We got off too, but didn't stay very long. We did eat lunch on the island, but because of the rain and wind it was not very enjoyable. To their credit, the Disney staff had extra activities on board and came up very quickly with a revised schedule.
There were a lot of people in line at the laundromat to use the dryer to dry their clothes. If you were not there right when your dryer cycle was up you would come back to find your clothes on the table. My cycle had not even ended, but I guess someone felt the clothes were dry enough and they took out clothes out and put them on the table. They must have felt a little remorse, because they did fold them.
The weather for the rest of the cruise was great! We did not do any excursions, but did things on our own. In St. Maarten we did some shopping, took a taxi and visted the French side, St. Martin and then went to the beach. In St. Thomas we rode the sky tram, also did some shopping and then went to Megan's Bay beach. Unfortunately, in St. Thomas we did not dock at the dock in town and had to take a taxi to get to the town.
We also drove to Atlanta. The drive was awful for us too. There was construction on I-75 around Valdosta that took us hours to get through. The traffic was backed up for many miles. When we finally got to the end we had found they had closed the Interstate to one lane. What should have been an 8 1/2 hour drive took us about 11 1/2 hours.
As far as the sea, it did get a little rough occasionally. Nobody in our party got seasick though. I heard some people did report feeling sick on their first night, but they seemed to have recovered from it the next day.
Overall, the cruise experience was great. Castaway Cay was a big disappointment because of the weather, but that was something that was out of everybody's control.