Utuado marks the southern border of Karst Country. It's a municipality at the dead center of the island that sprawls across the spine of the Cordillera Central mountain range. To experience the island's central mountains, continue driving up into the mountains above Lago Dos Bocas. After about 20 minutes you'll reach the Casa Grande Mountain Retreat, which is open from 5 to 8:30pm weekdays and 3 to 8:30pm on weekends. This establishment, a guesthouse and restaurant, serves upscale comida criolla-inspired dishes with vegetarian options. Café Casa Grande spills from a dining room and patio to a veranda overlooking a lush mountain valley. But you may want to spend the night if you dine too late. The property is reached via curving country roads, which can be tough to handle at night.

This is Utuado, a good base in the Cordillera Central massif overlooking the heartland of karst. Utuado is a stronghold of jíbaro (country folk) culture, reflecting the mountain life of the island as few other settlements do.

Just south of here you'll hook up again with Rte. 111 going west to Lares. You'll almost immediately come to Parque Ceremonial Indígena Caguaña (Indian Ceremonial Park at Caguaña). The site is signposted and need not take up more than 30 minutes of your time. Built by the Taíno Indians some 1,000 years ago, the site was used for both recreation and worship, and it is encircled by mountains near the Tanama River. You can still see the outlines of the ancient bateyes (ball courts), which are bordered by carved stone monoliths decorated with petroglyphs. The best-known petroglyph is the much-photographed Mujer de Caguaña, a figure squatting in the position of an earth-mother fertility symbol. There is a small and very minor museum of Indian artifacts and skeletons on-site. The site is open daily from 8am to 4pm. Admission free. For more information, call tel. 787/894-7300 (Rte. 111, Km 12.3).

From Lares, take Rte. 129 south to return to Arecibo, a good spot for a meal before taking the expressway back to San Juan.