The interior of Puerto Rico - in the Cordillera Central, which runs like a mountainous rudder, east to west, along the length of the island - is best explored along LA RUTA PANORAMICA . A 165-mile assemblage of about forty roads, the Panoramic Route can be heartstopping - not just dazzlingly beautiful, but twisting through mist-shrouded, folded peaks, often without dividers, and sometimes with precipitous drops on either side of the narrow road.

In the mountains, the temperature is much cooler, the air heavy and wet, and the vegetation lush and jungle-like. You'll hear sounds of roosters and coquís and see houses built on stilts and towns wrapped in fog, seemingly lost in time. You'll catch glimpses of both the Atlantic and the Caribbean at various points along the route, which bypasses canyons and forests.

The road begins in Yabucoa , a beach town on the east coast, and ends at Mayagüez; to do the entire length without stopping would take a whole day. Plan on at least two days and take your time on the often harrowing roads. Unless otherwise indicated, all the stops described below lie directly on the route, so follow the Ruta Panoramica signs carefully as you drive, as the route numbers change often.

The first major stop is the town of Guavate , legendary for its lechón , juicy roast suckling pig cooked on an outdoor spit. For the best lechón , turn south off La Ruta Panoramica onto Route 184; at km 27, half a dozen restaurants specialize in selling the tasty meat, most notably Lechonera El Rancho Original and El Monte . Customers are charged by the weight of their plate (about US$6 a pound). Locals come in droves on the weekend, when live music fills the outdoor seating area.

Many sanjuaneros come to this area for the 6000-acre Reserva Forestal Carite (tel 787/745-4545) in what is known as the "Guavate region", less than an hour south of San Juan, where you can hike, camp, fish, bird-watch, swim and escape the heat. Three rivers originate here - the Rio Grande de Loíza, the Rio Grande de Patillas and the Rio de la Plata; the reserve, which stretches over the Sierra Cayey, was established in 1935 to protect this important watershed from erosion caused by development. It is home to two campsites and 25 hiking trails , the most popular one starting from Charco Azul , a bluish freshwater swimming hole within walking distance of Route 184. You will see signs for Carite on 184 between La Ruta Panoramica and the lechonerías farther south on 184.

Turn back on 184 and continue west on 179, 7741, 7737, 7722 and 7718 to San Cristóbal Canyon , a stunning, 500-foot-deep gorge that stretches for five miles and is home to Puerto Rico's highest waterfall , on the Río Usabón. The gorge, visible from the intersection of routes 725 and 162, is hard to access on foot without trespassing on private land, and the slopes can be very dangerous. You can hike it, but it's best to go with an organized tour. Groups leave from La Piedra restaurant (tel 787/735-1034) on Carreterra 7710, km 0.8, next to the Parque Mirador, at 8.30am on Saturdays; call ahead to make a reservation or to arrange a private hike. Bring water and sturdy hiking shoes.

On Route 162 the charming little mountain town of Barranquitas is best known as the 1859 birthplace of Luis Muñoz Rivera , champion of Puerto Rican independence before Spain ceded rule to the US. Rivera is remembered at the Casa Natal Luis Muñoz Rivera on Calle Luis Muñoz Rivera (daily except Mon & Thurs; 1-4.30pm; free; tel 787/857-0230), a museum in the very simple criollo home where Rivera was born. Meanwhile, the Mausoleo Familia Muñoz Rivera , 7 Calle Padre Berrios (same hours as Casa Natal; free), contains the remains of Rivera and his son, Luis Muñoz Marín, another extremely important political shaper of modern Puerto Rico and founder of the Popular Democratic Party. If you get hungry, Bar Plaza , Calle Barcello (tel 787/857-4909), on the plaza, is an inexpensive repostería dishing up excellent roast chicken with rice and beans for US$4.

From Barranquitas, head south on Route 162 to Route 143 west, an uphill drive which will take you to the 7000-acre Toro Negro Forest Reserve . Three thousand feet above sea level, this ten-mile stretch of La Ruta Panoramica takes you far from civilization and over the highest peak in Puerto Rico , the Cerro de Punta, at 4389 feet. This is easily the most tortuous, narrow stretch of the route; landslides are common, and fog can be thick. The views, however, are stunning when the mist clears, and at km 40, a rare vista of both coasts awaits the intrepid traveller.

You'll find a ranger station at km 32.4 on Route 143 at the Area Recreativa Doña Juana, but their maps are virtually useless. If you want to camp , you can pitch a tent not far from here at Los Viveros at km 3.2. Apply for a permit fifteen days in advance at the Department of Natural Resources in San Juan (tel 787/724-3724).

Maricao , near the western end of the La Ruta Panoramica, hosts a coffee harvest festival in mid-February, but its natural setting alone makes it worth a visit any time of year. The town is snug in the mountains, with some steeply inclined streets, and gorges and streams just on the outskirts. Don't think about finding the perfect cup of coffee during your stay here; even the most authentic-looking joints in town sell imported stuff.