Eric, I wish it were easy to describe the directions to trailhead. On the scheduled ride, we needed to enlist my good friend (who lives in SLO and knows the area) for assistance to help find it. Its relatively easy to get to the entrance of the OHV park (off Hwy 58), but unless you go with somebody who knows the exact entrance to the trailhead, the average 'outsider' would never find it. You're riding along a fireroad, and then there's this unmarked small clearing off to the left that disappears into a thicket. As it turns out, there is a 14" wide trail cut into the thicket and the rider disappears into the bush.
The ride is great, but with some very challenging (technical and steep) climbs. I would describe the ride as three segments 1) fireroad then single track with steep climbing, 2) rolling single track with 5 or 6 creek crossings, 3) gradual and long ascending single track to the top. Total ride length is just under 20 miles, but you feel like you've ridden 50. Bring some snacks and plenty of H2O.
I recommend going with someone who knows the entrance to trailhead, plus there is a small road between segments 2 and 3 that requires a bit of directional guidance. Otherwise, watch for a future scheduled out-of-town ride with the SSFTA.
Mark