If you are running the coast - why not do a little of both camping and hostels. Cal state parks have great hiker/biker campsites - often set off from loud car campers - and you really just can't beat hostels like Pigeon Point for unsurpassed beauty. Usually when I'm inside, I stay up later talking to folks and get up later the next morning - no big deal. Hotels on the California coast tend to put a big dent into your wallet - especially during touring season. If you are going all the way to San Diego - consider doing Mulholland Drive and the mountains around L.A. rather than going thru. Or you can cut east along the Cuyama valley on Hwy 166.
Best - J