Many people ask about California central coast travel times. I'm posting this thread here so it can go in the "Top Questions About Big Sur" section (upper right corner of the Trip Advisor Big Sur home page) for easy, permanent access.
Of course, these times are estimates, and will vary depending on traffic. You should also check the California Department of Transportation website before you go, as it contains detailed, updated information about road closures and construction.
LAX to Santa Barbara: 2 hours. Get on the 405 north, then exit to the 101 north. The 405 is also confusingly signed as the "San Diego Freeway" but it goes there only if you head south.
Santa Barbara to San Luis Obispo: 1.5 hours on the 101. An alternate route if you're interested in mountain scenery: exit to Hwy 154/San Marcos Pass Road. It rejoins the 101 just north of Solvang. The driving time is approxmiately the same.
San Luis Obispo to Cambria: 1 hour. Exit the 101 onto 1. San Simeon/Hearst Castle is less than 15 minutes further north after Cambria.
Cambria to Big Sur "village" (around Pfeiffer Big Sur State Park): 2 hours on Hwy 1, without stops, but plan on more time to park at the scenic turnouts and enjoy the views.
Big Sur village to Monterey: 1 hour. Travel on Hwy 1.
Monterey to San Francisco: 2-3 hours. There are several routes: Hwy 1, the slowest, but right on the ocean; Hwy 1 to 17 to 85 to 280, which goes through gorgeous mountain scenery; and Hwy 1 to 156 to 101, which may be faster but is less attractive than the other routes.