I'm a SoCal native now living in northern California, and thought I'd post some of the best CA roads I know of, and maybe others can add theirs.

Everybody knows about PCH/CA-1, Mulholland Hwy, and Angeles Crest Hwy (partially AKA Angeles Forest Hwy). They may also know about Little/Big Tujunga Cyn Rds courtesy of Matt Farah/Smoking Tire, so those are the obvious ones to get out of the way.

Others I've driven and can recommend include:

tight twisties
CA 229 Webster Rd
CA 33 Ojai to Ventucopa
CA 58 McKittrick to Sta Margarita
CA 198 Coalinga to San Lucas
CA 25 Airline Hwy Hollister to Pinnacles
CA 74 Ortega Hwy

tight twisties & long sweepers
CA 178 Bakersfield to Lake Isabella

long sweepers
CA 84 Vallecitos Rd

I'll add to this list as they come back to me.