>>1473866>>1475510A caveat, the general rule in NorCal/Southern Oregon is that the farther east you go, the more isolated you can get.
I've still never been to the Redwoods or Humboldt, but I know that the Siskiyou/Shasta forests and Winema near Klamath are fucked. All the good campsites are populated by Bendites and tourists, and all the unpopulated areas are fucked scrublands with drunk Injuns still living Wild West fantasies.
Plumas is probably an exception to this rule, since it's so close to Reno, but I've also never been there so don't take my word on that.
The Tule (Too-Lee) Lake area isn't traditionally beautiful, but I personally love high desert. The Lava Beds monument has some kickass frontier history to it, and in that area is also an old Japanese internment camp (where George Takei grew up, fun fact). Tourists love it, but not in this time of year.
And yes, all of this shit is dramatically out of the way. It will be a chore to get places, but if you think you're getting a good camp experience near Mendocino or Chico you're delusional.