Although the Trabuco Canyon Trail is travelled in both directions, it is traditionally ridden downhill and most often used to complete an up Lower Holy Jim Trail
, Main Divide, down Traubuco Trail loop. It is also used as the final downhill for the annual "Vision Quest" race.
The trail is 100% singletrack, starting to the right around a green guard barrier and heading down immediately. You'll start in deep shade but the trail will alternate between shade and sun. The trail definitely has a "beginning, middle, & end." The beginning is nice - a little loose and occasionally rutted, but mostly fun & easy going. There are some g-outs, some chances to appreciate the view. At a 90-degree left turn, keep an eye out for the "Christmas Tree" that gets an ornament or 2 around the holidays.
You'll know you're in the 'middle' section when the shale begins and the shade goes away. Did you check your sealant before starting the ride? This section requires some caution, you're riding on sharp gravel and while there are no 'drops', there are some steep -15% spots. Don't lose focus - this is not a wide trail. This section is best a few days after a rain.
Shortly after the shale ends, you'll come to Trabuco Creek, a mostly dry wide rocky creek crossing where you'll likely have to dismount. Once on the other side, the grade decreases and the trail gets really fun. You'll get some cool technical challenges - boulders, roots, etc. Likely 1-2 more dismounts and watch for hiker traffic here before you get to another green guard gate which notes the end of the trail. It's unlikely you have a car parked here, so continue on the fire road to either the Holy Jim parking lot or all the way out the Trabuco Canyon Rd