Fabulously scenic Highway 164 leads northeast from Bagaces and climbs steadily up the western shoulder of Miravalles Volcano (2,028 meters). The almost perfectly conical volcano is the highest in the Cordillera de Guanacaste.

The western slopes are covered with savanna scrub; the northern and eastern slopes are lush, fed by moist clouds that sweep in from the Caribbean. The southern slopes are cut with deep canyons and licked by ancient lava tongues, with fumaroles spouting and hissing like mini Old Faithfuls. The forests, replete with wildlife, are easily accessed from the road.

Highway 164 runs via the village of Guayabo, 21 kilometers north of Bagaces (it has a bank and Internet café). It is paved as far as Guayabal, seven kilometers north of Guayabo, then gives way to a hellishly potholed road as you descend five kilometers to Aguas Claras and, beyond, the hamlet of San José in the northern lowlands.

There’s a Canopy Tour (tel. 506/673-0697, www.volcanoadventuretour.com) seven kilometers north of Guayabal. There's also a rustic restaurant. Call ahead, as the facility was closed when I last visited.

Be sure to call in at the Art Gallery & Information Center (tel. 506/673-0662, www.tonyjimenez.com), midway between Guayabo and Guayabal.

Finca La Anita (tel. 506/388-1775, www.fincalaanita.org), a macadamia farm near Colonial Libertad, on the northeast slope of Rincón de la Vieja Volcano. Guided tours are given by appointment.

A loop road from Highway 164 leads east via the community of Fortuna and Las Hornillas (Little Ovens), an area of intense bubbling mud pots and fumaroles expelling foul gases and steam. Here the Costa Rican Institute of Electricity (ICE) harnesses geothermal energy for electric power, with two plants that tap the superheated vapor deep within the volcano’s bowels. You can visit the main Planta Miravalles geothermal plant (tel. 506/673-1111, ext. 232), about two kilometers north of Fortuna, by appointment.

The touristy Centro Turístico Yökö (tel. 506/673-0410, fax 506/673-0770, www.yokotermales.com, $5 admission), is a recreation park amid lawns one kilometers west of Las Hornillas, with five clean thermal pools (ranging 30–50°C) set amid 13 hectares; one even has a waterslide and a manmade cave that serves as a sauna. Massage is offered, as are horseback rides ($15, four hours).

Centro Turístico Yökö also has 12 spacious cabins ($30 s, $50 d) with verandas with volcano views, plus ceiling fans, and large private bath and walk-in showers with thermal water. It has a restaurant with TV. Rates include breakfast and use of facilities.

Nearby, Centro Turístico Termomanía (tel. 506/673-0268 or 506/822-2602, $4) competes; the highlight is the hornillas—bubbling mud pools and fumaroles—immediately adjacent to the property. It’s totally unguarded and very dangerous—keep your distance!

In Guayabo, the Hotel Primavera (tel. 506/673-0382) offers simple but clean cabins.