The movement of the boat is fairly gentle. Many people find it soothing and have a tendency to sleep like the dead on ships. Breezes could be an issue as you will always find one on deck. Of course you can just hole up except for periods when the boat is docked and then go topside. People may be an issue as well depending on how crowded the boat is. For getting on and off the ship from port stops there will be lines you have to wait in and also when getting food unless you have a suite and they can bring meals to you. I think it's worth a call to the cruise line to see how they can accommodate you for these activities. If you decide to go you can always check about departing early at one of the ports if needed.