Bruce Gordon BLT, Cannondale parts bike, Ecodyne recumbent trike, Counterpoint Opus 2, miyata 1000
Paved or unpaved? The old unpaved stage road over to Hopland is a classic and much quieter then the paved road. Taking hwy 29 up to the Robert L. Stevenson park then dirt to the top of Mt. St. Helena would be a long steep one. For an over-nighter try going to Wilber Hot Springs in Colusa County. Tha area has an annual ride around the lake. The local 600 K. Brevet ride goes from Hopland, around the north side of the lake, past Berryesse Lake to Davis and back. For a short ride go to the Richardson Rancheria indian Casino for a cheap meal and return.
I do enjoy riding the roads and usually just do a clockwise loop around the lake when I go visiting. Be sure to take Sulpher Spring Rd into the Mts just north of the town of Clear Lake, and if you want a good climb, go up to Cobb Mtn.
I personally dislike Jago Baty Rd and how it takes you into K'ville. it is very narrow with lots of traffic. I'd prefer to stay on the main road, there is good shoulder most of the way in to K'ville. I enjoy the climb, the scenery, and the descent on Cobb. The last loop of the 100 mile course is interesting in that it takes you into some old areas with lots of junk... think red neck. Only place in the county I've had to deal with a dog.
Do be aware, pavement all around the county is lacking maintenance, the worst area is around the Town of Clear Lake. It would surprise me to find there was only one bike shop in the county, Lakeport, so be prepared for self support, don't count on finding even tires and tubes outside of Lakeport. I've had no problems with cars on any of my trips, anytime of year.
If you PM me, I think I can send you the course info from a GPS log from last years ride
I was also looking for routes/loops around the area, and thought I'd update this topic w/ a link to the Lake County Visitor's site page for bike routes. It appears that only the loop for "Scott's Valley" and "Around the Lake" are fleshed out w/ a map and directions. The other links display a brief summary. I may try some of the Scott's Valley section if the temps. stay under the 90's next wk.
A recently opened LBS along S. Main in Lakeport (Bike Rack: 707-263-1200 - not affiliated, etc.) warrants a visit, too.