This is a remote and very low traveled dirt and gravel road in northwestern Sonoma County.
We have ridden the route 4 times - once on a road bike (28mm tires), once on an MTB and twice on a cross bike. It is completely manageable on a cross and mountain bike, and on a road bike as well for ascending (it is not advisable to descend on a road bike as there is a high chance of pinch flats). The climb itself is from the coast up to Seaview Road which is part of the very popular Cazadero-Kings Ridge-Seaview-Fort Ross Road Loop. We are surrounded by redwood forest and ferns most of the route.
This is a very peaceful and pleasant climb which should be done at least once by all local cyclists and is worth the effort to get there if you are staying nearby on the coast.
The roadway is effectively single lane with no shoulders and is dirt/gravel its entire length. However, there is very little traffic and motorist will likely be traveling slowly when you do encounter them.