I just returned from leading a cycle tour down the California coast from the San Francisco Bay Area to Santa Barbara. The classic Bicycling The Pacific Coast, by Vicky Spring, was an indispensable reference and a major part of my trip planning process.
For the section of interest to us (central coast of California), Bicycling the Pacific Coast routes you down Highway 1 (California State Route 1, a.k.a. the Pacific Coast Highway) nearly the entire way. The book provides turn-by-turn instructions that explain when it is advisable to deviate from Hwy 1 (either when bikes are not allowed on the highway, when there is a scenic detour with less car traffic, or when there are specific points of interest), and exactly how to do so. It explains when food, water, restrooms, and lodging are present along certain segments, as well as when they aren't. These elements are (understandably) missing from guidebooks that assume you are traveling by car.
Elevation profiles of each day's ride are also given, which was handy for mentally preparing my travel-mates for each segment. Points of interest and other considerations for cyclists (such as when there is a wide shoulder, and which segments get really hot in the summer) are noted.
Although the book is oriented towards expedition cyclists (i.e. cyclists who carry a tent with them and stop at a campsite each night), and our group was doing credit-card touring, I had little difficulty adapting the suggested routes to stop each night at a city rather than a campsite. It is also straightforward to follow the suggested route but lengthen or shorten each day's ride, depending on your taste.
I purchased a copy of the book on Google eBooks and loaded it onto my phone, so I was able to consult it on the road as well. You can do something similar with the Amazon Kindle edition.
Route planning for a cycle tour of the coast is an optimization problem in many dimensions, and you will need to consult maps and references other than Bicycling the Pacific Coast, but this book helps to pare down the search space considerably and make it much more manageable. Highly recommended.