Not sure how much of this route you've done previously, but to my knowledge Pine Mt Rd dead ends and you can't get through to Adobe Creek.
The most dirt I know of to get up to Cow Mt would be to take Ida Clayton to Western Mine (dirt for a mile or so), then after Middletown, Big Canyon is dirt for about 5 miles, then Siegler Springs has some dirt. I think you then have to go to Lakeport to get to the dirt road through Cow Mt, but I'm not sure about that. Also, the Old Toll Rd which parallels Hopland Grade is dirt and a good ride.
Curious to hear how it goes.
Ginormous Beasts go to the Eastside
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