My two grandchildren, 11 1/2 yr old boy and 7 yr old girl, just returned from a 7 day Holland America Western Caribbean cruise. They just loved it.
The ports, Key West; Belize City; Santo Tomas de Castilla, Guatemala; and Costa Maya, Mexico, were wonderful for the kids.
They enjoyed Club HAL, the kids' activities. Because of the age difference, they were in different groups, but both enjoyed the time spent with the kids' activities. The staff was wonderful. Between the port excursions and Club HAL, we spent only one full afternoon at the pool, which they also enjoyed.
Good location near aft elevators, so very convenient to get to dining rooms, swimming pool, library. Rm was quiet. My first time in an inside cabin, but it was not as dark at night as I had heard; some light leaked under door so you could walk in the dark in the room, but not in the bathroom. It was crowded with 3 passengers (couch opened up and was left open during the cruise), but for two would be about the same as an outside cabin across the hall. The couch opened parallel to the wall, not out into the room. When water was a little rough, I felt it less in the cabin than on higher decks.
Our a/c worked very well and we adjusted it during the day: cooler at night and warmer after coming from the pool.