Side note: With Southern California's huge population base and lots of relatively dark Mojave Desert, with so many clear, relatively warm nights per year, I always wonder why no-one has yet attempted to start a formal astronomy community in California? Perhaps someday...
For retired folks moving TO California is a no go. So it would have to be cheap enough for people to maintain a residence outside of California. An RV park design coupled with homes might work, but can you get the price low enough given all of California's permitting requirements.
I would look in the coast range west of Redding. Some real dark skies there and pretty empty country,
AND just north of San Luis Obispo. Weather is better in winter and I suspect so would have some buffers from development with the Forest Service and military lands in the area.
Plus either location would probably get lots of use from California residents.
Having been back to the southwest deserts for the first time in 30 years....the skies are heading south at a rapid pace.
California might be better in the long run.