Princess Cays is a beach, with some shops and Princess will have food there and and servers on the beach so you can get drinks.
There seemed to be plenty of watersports, I did the Banana Boat ride and it was a total blast..got thrown off twice.. I am sure your kids will love it..other than that, mostly chilling and swimming, etc.
It was much nicer than I expected, so I hope you enjoy it..
1999-Carnival Sensation, 2000- Inspiration, 2001- Destiny 2002-Celebrity Galaxy, 2003-Constellation, 2004-Constellation 2005-RCCL-Adventure of Seas, 2006-Constellation
2007-RCCL-Seranade&Explorer of Seas