Check out Capt. Jay's suggested itinerary - http://www.traveltalkonline.com/ubb...thomas-st-john-itinerary.html#Post245664
My daughters both started swimming with mask and fins without snorkel at 5. They started with a flotation vest and had confidence to leave it behind after 3 or 4 days, while supervised by Dad. They loved Hawksnest, Trunk Bay, Maho Bay, Salt Pond, and Little Lameshur on St. John. Round Bay/Hansen Bay with Pelican Rock is a great overnight. Dinghy to Cruz Bay from Caneel Bay for a night on the town. Good ice cream at Mongoose Junction. Dinner with kids, I would recommend High Tide, Banana Deck, Lime Inn, and Greengos for casual dinners.
Coral Bay is an option for a dinner out on St. John. Skinny Legs, Rhumblines, Ekaete Pink Corner, Coral Bay Caribbean Oasis, Salty Mongoose, and Aqua Bistro are options. Pizzabar in Paradise is between Sanders Bay and Johnson Bay. You can anchor just inside the channel markers to the West in Coral Bay.
Christmas Cove at Great St. James, Magens Bay, Brewers Bay, and Druif Bay Water Island are other options. We really like the scene at Water Island and Dinghy's Beach Bar.