Hi bbritten, welcome to Cruise-Chat. I removed the direct link for Real St. Lucia Tours. We're not allowed to advertise on this site. It all depends on what your family's interests are as to what would constitute the perfect excursion. We love snorkeling and have done some great snorkels in St. Lucia, usually through the ship. We've gone to Pigeon Island, and have done a few land tours. St. Lucia is one of my favorite islands. The snorkel of the Pitons was outstanding.
You can use the "find" feature in your upper left hand corner and type in St. Lucia. It will pull up all the posts made and you might find something that interests you. Best wishes!