After the beaches have been combed, the waters snorkeled, and the duty-free shops plundered, one's Caribbean quests need not be at an end. Those who hunger for more may be surprised to find historic and architectural jewels waiting to be climbed about and picked through - hilltop fortresses, vine-covered great houses, ancient churchyards.
One of the most ambitious restoration projects in the West Indies, well under way but far from finished, is Nelson's Dockyard, a sort of marine Williamsburg on the island of Antigua. Horatio Nelson, who was later to destroy the French and Spanish fleets off Cape Trafalgar (where he himself died), spent some swashbuckling years in the islands and during the 1780s commanded a dockyard encompassed by the high green bluffs of English Harbour, on Antigua's southwest coast.
''This is the only Georgian dockyard left in the world,'' Charles Jane, a local historian, told me one morning as we wandered about the two-acre restoration site, a collection of period stone buildings, patches of green lawn, and tangled ruins. Mr. Jane provides historical counseling to Ted Stevens, a bearded Englishman who has been dispatched from London to head the project. They agree that Nelson's Dockyard can use the Mystic Seaport in Connecticut as a model, but that it should breathe more freely and appear less contrived.
To that end the one-time Officers Quarters, a sprawling two-story building hard by the quays, where sleek yachts from Bermuda, Greenwich, Conn., Malta, and Toronto were tied up that morning, has become an appealing warren of shops and businesses operated by young local talent. Aaron Challenger turns out handsome silk-screened tea towels and T-shirts; Cecil Smith runs a picture--framing shop; and downstairs Peace Corps volunteer Lou Cottage helps island teen-agers sell the paintings they do in his workshop.
No stuffy outdoor museum, the dockyard moves to its own West Indian beat. On the lawn near the quays, kerchiefed women, disdaining the use of scales, sell their onions, carrots, and bananas by the pile. In the shade of an ironwood tree near the walled entrance to the dockyard, taxi drivers waiting for business play games of warri, a kind of ancient African checkers.
Mr. Jane and Mr. Stevens agree that the closest thing to Nelson's Dockyard in the Caribbean is Brimstone Hill on St. Kitts, just to the west. This massive hilltop fortress has been partly restored, with exquisite taste, by the combined efforts of various Caribbean conservation groups. Today when one feels the need to beat a retreat from the beaches, the thing to do is mount Brimstone Hill, spread out a picnic near the ramparts, and drink in the sea views far below, where in 1794 the British defeated the overconfident French Admiral de Grasse.
On Haiti, you can make a pilgrimage to an even more stalwart fortress, the remote and bizarre La Citadelle, often called the eighth wonder of the world. The despotic black emperor Henri Christophe commandeered 200,000 former slaves to build the fort at the turn of the 19th century, and their forced labor produced walls 140 feet high and 12 feet thick at the top of a steep, jungly trail. By donkey or horse you climb that trail today and, passing through massive iron gates, enter a medieval world of cisterns, dungeons, and cannon galleries.
Not nearly so intimidating, but no less impressive, is the fortress El Morro on Puerto Rico, just a few blocks from the brick lanes, colonial mansions, and upbeat shops of Old San Juan. On weekends islanders flock to the vast green lawns around the fort to fly kites in the high breezes off the Atlantic, kick balls, and lay out picnics.
Volcanoes, which for better or worse have played an important part in Caribbean history, are compelling attractions on many islands. The best known is Mt. Pelee, which erupted in 1902 and destroyed the city of St. Pierre, killing 29,000 residents. You can walk among the broken statues and overgrown boulevards of the ruined city, and the long-silent volcano can be climbed in two hours, although a hired guide is advisable to negotiate the tricky going.
On Martinique's cousin island of Guadeloupe, the volcano La Soufriere has never done the damage of Pelee, thank goodness, but now and then threatens to blow. It is officially a dormant volcano, bubbling and smoking, but doing little else. It draws admirers to its slopes to try its many hiking trails or to take in the splendid views of Dominica and Les Saintes, off in the misty near-distance. Another lure is the Relais de la Grand Soufriere, an attractive guesthouse, hotel training school, and fine lunch shop on the lower slopes.
In the Dominican Republic, which shares the island of Hispaniola with Haiti, the nation's colonial heritage greets you at every turn. Downtown Santo Domingo has turned countless stone buildings with mahogany plank doors into museums, shops, restaurants, and hotels. The crowning achievement is Alcazar, the palace built for Columbus's son Diego, a marvel of intelligent reconstruction, finished in 1957.
On some islands, history and tourism have gone into partnership, producing, for example, hotels and inns from historic great houses on Jamaica. On little Nevis, at least five of the island's eight or nine hotels - Montpelier, Zetland, Golden Rock, Nisbet Plantation, and Croney's - are built around one-time sugar mills. You needn't step off the grounds to be whisked back 200 years. That's the Caribbean I treasure.