Long Canyon is the southern continuation of Fiske Creek along the western rim of the Blue Ridge. It is easily accessible via a pleasant oak studded approach road on the Knoxville Berryessa Rd south of the Napa county line and the McLaughlin Mine.
You basically hike up the canyon for a mile or two, gain one of two ridges sporting obvious firebreaks and make your way up one of those to the rim. From there work your way north till you pick up the southern branch of the Blue ridge Trail and follow it to the summit of Lowery.
Anticipate 12-14 miles round trip. This hike is doable in winter so long as the road isn't flooded. In winter it has a completely different character than the Lower Camp approach from Hwy 16, harkens back to a California that is sorta hard to find these days.
This is a remote trailhead that can be isolated in the event of flash flood, so don't play around with the weather if you value your car. Don't leave valuables in it either.
The correct parking spot is at a turn in the road where and obvious pullout leads to a corral with white sheathed steel posts. Follow that farm road over the gate and up the creek to Long Canyon.
This is a GREAT HIKE. I did quite a bit of pruning along the ridge but more is needed so take the loppers. Class 2 in places for sure with a few steep spots but nothing dangerous.
Note that as of Jan 2009 Rayhouse Rd is permanently closed. The Low Water bridge over Cache Creek is broken and the county doesn't want to spend a million bucks on a bridge used mostly for one company (the rafting company' access to Buck Island), tweakers, drunks and NRA nutbergers. So the county elected to discontinue maintenance on the road. The net net is this removes the easiest access to Lowrey, the southern terminus of the Blue Ridge Trail. One can still get to Lowrey from Fiske and from Long Canyon.