The trip is possible in a matter of days depending on what you want to see and do.
It's true that going "inland" will assure warmer temperatures but you will miss the amazing coastal drive.
Suggestions:
Redding (Jack's Grill)
Sequoia and Kings Canyon National Park
Lake Tahoe
Yosemite :thumbs:
Napa Valley/Sorrento/Calistoga (wine, spas, more wine)

:thumbs:
Sausalito
San Francisco/Berkeley/Oakland (food, alcatraz, fisherman's wharf, Coit tower, Golden Gate Bridge, Golden Gate Park, ball parks, hotels up the ying yang........and restaurants, could spend an entire week here) :thumbs:
Santa Cruz/Monterey/Carmel (Big Sur, golf, Monterey Bay Aquarium)
Cambria Pines/Hearst Castle (sick layout, Willy Randolph had too much money and not enough time) :thumbs:
San Luis Obispo (micro brews, college town)
Santa Ynez, Solvang (wine, food, movie Sideways local, mini Scandinavia)
Santa Barbara (shopping, food, nice downtown bar local on State Street, the Queen of the Missions, the wharf, beach art show on Sundays, the California version of the Riviera....and romantic) :thumbs:
Los Angeles (Hollywood, Dodger's Stadium, Rodeo Drive, too much stuff to list)
San Juan Capistrano
La Costa Resort
Del Mar
San Diego
You would be hard pressed to do all of these in an eight day period but you could hit some big areas.
That should whet your appetite!
Good luck with it.
Charlie