Old Caz is a rural West Sonoma County Road that is paved coming from Guerneville, but dirt, gravel and pine needles on its back side. A nice loop (cross bike recommended) is to begin in Duncan Mills and ride 23.8 miles (2,476’) from Duncan Mills to Monte Rio onto Old Caz Road (gravel much of the way and cross East Austin Creek at mile 14) to Cazadero then back to Duncan Mills (Map). It is recommended this ride be done during the summar as it is much easier to cross Austin Creek when the water flow is much lower.
This is a short but rugged climb at 9.9% average grade. The roadway is very narrow, but traffic is scarce. Kings Ridge can also be included in this loop if one is up for a more stout climbing day.