Visit Sulphur Springs definitely and Marigot Bay. The Dennery Fish Festival is also great, it's like a cookout on the beach at night with lots of music & dancing. If you go to Castries, it shouldn't be hard to find a good local tour guide to show you around and often get into places a lot of tourists don't get to see. My mama's St.Lucian and I've got an aunt who lives out there and she hooked us up with a really good tour guide when we went out to visit. I'll try and get in contact with her and PM you his number if she can find it. Enjoy St.Lucie!