On Av. La Florida leaving Santiago, take Route G-25 that leads to San Gabriel. Another option is by Av. La Florida or Av. Vicuña Mackenna until you reach Puente Alto. On Eyzaguirre street, turn left towards Las Vizcachas and get on Route G-25.
Approximate travel time: 50 minutes from Plaza Egaña to the Plaza de San José de Maipo
There is a bus line that departs from the San Borja Terminal in Central Station, every half hour. The trip takes 2 hours. Another option is to take line 5 of the Metro and get off at the Plaza Puente Alto Station and then a bus or bus that says "Cajón del Maipo", these also make the tour Vicuña Mackenna, Concha y Toro, Eyzaguirre, Vizcachas to the Camino Cajón del Maipo Volcano