This trail has two attitudes. At the top it is flowy singletrack through the chaparral. But once you get down into the canyon it is a rock garden like the nearby Romero Fire Road
You can ride San Ysidro as a loop by climbing up the Romero Fire Road
and transition to the trailhead across East Camino Ciello.
Hikers are frequently encountered on this trail and occasionally horses. Please ride with a bell.