San Pablo Cuatro Venados is a small town in the mountains SW of Oaxaca that features a small ecotourism reserve. This ecotourism features short hikes, gorgeous waterfalls, views of the valley below, and cabins to stay in.
You can catch a collectivo (ask for la linea de autobuses Teotzapotlan) to San Pablo Cuatro Venados from the second class bus station. One bus leaves at 3pm to Buenavista and the last one leaves at 4:30 toward San Mateo Tapanatepec. Ask the driver to be dropped off at San Pablo Cuatro Venados.