Hello, lreslock.
There are some nice beaches and some fairly interesting snorkeling spots, but they're not "world class". Where Nevis excels is in it's friendly and welcoming locals, it's natural beauty, and excellent plantation inn restaurants around the island.
I'd recommend that you sail to Charlestown, Nevis to clear into the Federation, then take a
mooring ball at the south end of Pinneys Beach, near the Double Deuce restaurant/beach bar. Most cruisers hang out their and they have free
WiFi. It's an easy walk up the beach to Sunshine's, Randy's Lime, or Chevy's, three other beach bar/restaurants.
At
Customs, ask for the following anchorages in St. Kitts to be included in your cruising
permit: White House Bay, Ballast Bay, Shitten Bay, Majors Bay, and Cockleshell Bay. In Nevis, Pinneys Beach, Tamarind Bay and Oualie Bay are enough. Then you'll be covered for anything you want to do. Chris Doyle's sailing guide for the
Leeward Islands has a great sketch chart showing these locations.
You can arrange a snorkeling trip with Barbara Whitman, a
marine biologists and very nice lady, or you can go on your own. The best snorkeling is in Shitten Bay and near the rocky points at either end of Majors Bay. Mostly
fish, not much pretty
coral. On Nevis, you can snorkel from the beach out to the rocky point at Cliffdwellers, and the stone breakwaters in front of the Four Seasons Resort are also of interest. Pinneys Beach is about three miles long and has plenty of sand. It's not isolated, but it's
never crowded. Lovers' Beach on the north end is very isolated and also very pretty.
It's worth it to have a three to four hour taxi tour of the island, stopping at the Golden Rock Plantation Inn for lunch. Ask for a table in the gazebo overlooking Redonda and Montserrat. Order the lobster salad sandwich. Trust me!
If you want to take a land tour of St. Kitts, I can suggest an itinerary if you like.