Just a quick update...we booked a 2 bedroom condo at Compass Point this morning. With the kayaks, Crystal Caves nearby, pools, and of course diving & snorkeling I don't think we'll get bored over there.
Didn't respond earlier but glad you chose Compass Point. If I would have responded I would have suggested booking through Hotels.com (which worked for us) as we got a better deal than we could get through the rates posted on Compass Point's website (and that was taking into consideration car rental, diving, breakfasts, etc....) Ocean Frontier's service for diving is fantastic - they make it very easy for their guests. It is probably the best set up for picking up, caring for, and returning your gear of anyplace I've been.
On the East End, besides Crystal Caves, is the Botanical Garden (probably not the most fun for teens however.) A trip to Rum Point and an evening BBQ is fun. Starfish Beach is also near Rum Point and unless the starfish have migrated away, you can snorkel and find a lot of them.
We have parked along the north coast of the East End and found places to snorkel, but a great place is around the pier at Morritt's Tortuga Club which is about 8- 10 minutes down the road from Compass Point. We saw a reef shark (it must have gotten lost) swimming around the pier a few years back. There is a beach there also.
Restaurants to be sure to eat at that are nearby are
Eagle Rays right there at Compass Point (they have a buffet night),
Big Tree BBQ which is the big tree in the owner's front yard with picnic tables around it (just down the road), and
Kurt's Korner which is on the road that cuts north and south through the East End and only about 5 minutes from Crystal Caves and the botanical garden.
Have fun!