16th-century cities, luxurious resorts await island visitors EXPLORING PUERTO RICO

The island is encircled by two major routes: Route 2, which borders the western half, and Route 3, which runs along the eastern half. Route 1 bisects the eastern half of the island, running from San Juan to Ponce, while Route 10 serves the western half, connecting Arecibo to Ponce. Almost anything worth visiting -- such as the island's balnearios or public bathing resorts -- is within a few miles of these four roads.

The balnearios offer dressing rooms and picnic grounds. Some of the finest are located in or adjacent to the towns of Guanica, Vega Baja, Dorado, Catano, Isla Verde and Vieques. Most are closed on Mondays.

Luquillo, on the island's eastern edge, may have the most beautiful beach of all, and supervised horseback rides that will take you there are available at nearby Hacienda Carabali; [phone].

The balnearios also offer the added attraction of being genuinely public beaches. Access is unrestricted, so visitors get a good idea of what island life is all about.

Isabela, a small coastal city on the island's northwestern shore, offers scenery typical of most Puerto Rican towns -- quiet walks along the sea wall, a central plaza surrounding a monument or fountain, small restaurants offering inexpensive, basic food, and variety stores where you can buy tiny clay coqui (frogs native to Puerto Rico) for a quarter.

Some visitors who tire of the beach try something a little different -- a tropical rain forest.

Caribbean National Rain Forest -- [phone] -- is a 27,700-acre preserve administered by the U.S. Forest Service. Situated off Route 3 about 25 miles east of San Juan and known locally as El Yunque, the name of a 3,500-foot peak that dominates the area, the forest is crisscrossed by hiking trails and hundreds of tiny streams.

If you decide to spend some time in El Yunque, be prepared to get wet. Afternoon showers are almost automatic here. At upper elevations, the forest soaks up some 200 inches of rainfall every year.

Also be prepared to be impressed. Lush vegetation -- towering trees, massive ferns, dense patches of moss -- is the order of the day at El Yunque. Waterfalls, too, can be found almost everywhere.

The best place to start your visit is at the Sierra Palm Visitor Center, at kilometer marker 11.6. There, audio-visual exhibits will explain the natural wonders of El Yunque. Park rangers, fluent in English, can help tailor an itinerary.

End the day with a visit to one of the island's casinos, located within hotels such as the Caribe Hilton in San Juan, the Sands in Isla Verde or the Clarion in Miramar.

By the end of your stay, you'll no doubt find yourself agreeing with Ponce de Leon, who gave the island its name by exclaiming, "Que puerto rico!" -- What a rich port!

IF YOU GO . . .

For more information, contact the Puerto Rico Tourism Co. at 565 Fifth Ave., New York, N.Y. 10017, [phone]; or contact the Tourism Information Center, Luis Munoz Marin International Airport, Isla Verde, Puerto Rico, [phone].