When we were in ST. Kitts, we took a cab from town and went out to Turtle beach, nice beach and very scenic ride. Usually other cruisers will also be going out there and you can share a cab, less money that way too because its about a 45 minute drive. You can arrange with the driver to come back and get you at a certain time too. We had a lot of fun there, neat little monkeys in the trees that you can feed too.
I took the land excursion to the Brimstone Fort up the coast during my St.Kitts port call. It is a well preserved old fort that saw many battles between the Frence and the English. To get to the fort from the parking lot will take a bit of walking, but the view from above is well worth it.The fort is well worth seeing.
The tour will also stop at the Carabelle Batik Studio where you can view the batik process (wax resist) being used on wall hangings and clothing as they are decorated in vivid tropical colors. The Studio is in Rhomney Manor a converted manor house that sits in the midst of some beautiful gardens. The gardens alone are worth the visit. This is a good tour to take on this island. Enjoy.