I did a 7 day cruise in Tahiti, Bora Bora, Morea, etc... Only a couple of days were actual at sea, most of the time it was just several hours between islands. As long as you are on a cruise ship with a lot to do I'm sure it will be a blast. Reading, etc. is fun but you'll also need some variety to keep things interesting. Multiple restaurants to visit, different classes and activities will make it enjoyable. What cruise ship are you on? I went on the Paul Gaugin.