Getting There -- Continental Auto buses (Línea Sierra Norte) depart from the Plaza Castilla Intercambiador station hourly and the journey time is about 90 minutes. They operate between 6:15am and 11pm on weekdays and between 8am and 10:30pm on Saturday and Sunday. The last bus back to Madrid is at 8pm (tel. 91-314-57-55).
Driving, take the northerly N-1 highway, which leads straight through Buitrago del Lozoya on its way to Burgos. Once clear of the city, you should get there easily in an hour.
Visitor Information -- The town hall in Buitrago (tel. 91-868-00-56) gives useful local information.