Charlotte Harbor beckons visitors with its remoteness and hints of wealth

YOU don't have to visit the Caribbean to sail through subtropical isles, land on deserted beaches, or dock at exotic hideaways. Florida's Islands in the Sunset, which are among the state's last underdeveloped coastal areas, offer just such vacation spots for yachtsman and landlubber alike.

Charlotte Harbor, on the state's Gulf coast, is dotted with dozens of unusual islands. They can be reached from the north via Gasparilla Island, the once-exclusive resort of the du Ponts, or from the south via Captiva Island, billed as Florida's Tahiti. Accommodations range from dockside apartments to Victorian mansions.

You can get there on your own boat, of course, but if you're not a sailor, you can take Island Fantasy Cruises from delightful Fishermen's Village in Punta Gorda to Cabbage Key and Cayo Costa.

If you admire the charm of yesterday, start your vacation on Gasparilla Island, a great tarpon fishing center.

The village of Boca Grande is in few guidebooks; yet it has been a refuge for the rich since Sen. Henry Algernon du Pont opened his winter home around the turn of the century. There's no shopping to speak of on the village's Worth Avenue, only a few general stores and walls of bougainvillea hiding the residences of Weymouths, Symingtons, and Harrimans.

Since 1913, there's been only one hotel here: the Gasparilla Inn. This key-lime yellow winter resort, with its 64 guest suites and 16 cottages, still boasts the personal touches that made people like J. Pierpont Morgan regular customers. The huge yacht basin offers charter boats and experienced skippers for cruising or fishing.

Those who prefer the ultimate in modern luxury will want to visit South Seas Plantation on Captiva Island, the Tahitian-style winter home of the famous Offshore Sailing School. More than 500 rooms and apartments are spread along two miles of beach at the island's northern tip. The 3,700 feet of dockage is crammed with rental craft, and there's a golf course and 22 tennis courts nearby, with Wimbledon favorite Virginia Wade as host.

No matter where you decide to stay, your island-hopping should include Cabbage Key and Useppa Island.

The 1938 Cabbage Key Inn was the rustic home of mystery writer Mary Roberts Rinehart. Innkeepers Bob and Phyllis Wells have modernized the rooms and waterfront while preserving the island's Caribbean-like atmosphere. After sampling the restaurant's cuisine, you'll want to stay longer, or at least join the countless guests who've made it a custom to nail an autographed dollar bill to the ceiling or walls.

Useppa Island is the site of a luxurious private club built around New York entrepreneur Barron Collier's 1912 mansion. Potential members can visit the fine facilities where Zane Grey, Teddy Roosevelt, and Herbert Hoover were entertained.

There are dozens of deserted islands, as well, in Charlotte Harbor, and two of them - Cayo Costa and Cayo Pelau - deserve special mention.

Cayo Costa is Florida's last primitive barrier island, a magnificent expanse of white beaches and sand spits.

Lee County maintains docks and a public park at Pelican Bay Pass and picnic grounds and a pier on the northern gulfside.

A walk along shell roads overhung by oak trees leads to a pioneer cemetery and the ruins of farming villages. Don't be surprised to find wild horses grazing in the open fields.

Two miles east of Gasparilla one finds Cayo Pelau, legendary as a home of pirates and a potential site of buried treasure. The island's shell roads climb Calusa Indian mounds past the ruins of homesteads. The island has a lot to offer artifact hunters.

The vast expanse of Charlotte Harbor and the distance between islands has fortunately curtailed bridge-building and development. The Islands in the Sunset remain natural and distinct - a rare find among Florida's vacation destinations.