Howdy MrsW... Welcome the the forums. Whether your intentions are to grow a personal med garden, just require access to medicine from a co-op/dispensary or if your plans include operating a medical marijuana commercial venture (co-op/dispensary etc), the California marijuana medical
guidelines (Prop 215/420) apply for the entire state.
Each county may have their own specific med requirements/limitations under the Prop 215/420 umbrella, it just depends on the county. As far as any of them being more "friendly" than the next, when it really comes down to it, the basic law is still the law. In other words, if one abuses the Prop215
guidelines where ever you reside, you can and most likely will get yourself into trouble.
I can say the Northern end of the state is more liberal (from the San Francisco area to the Oregon border) which is to say, again, if you stay within the guidlelines, the powers that be in these areas do recognize and for the most part, work with the different communities in regard to the marijuana med laws and patient needs. An example of this is Oaksterdam University (they have a website) located in Oakland Ca , specifically created for those who want to learn all the aspects of med marijuana. Classes include how to grow your own medicine, legal aspects and even how to set up your own medicine related business ventures.
I would suggest you do some research into the different counties and their requirements/limitations etc by visiting the different County websites. Most all have a Medical Marijuana
Guidelines link. Note: None of them will indicate whether they are "friendly" or not (smile). In addition, the news department of this site does a wonderful job keeping members apprised of the latest medical marijuana related news/events thru out California. Great job guys!
Currently, the southern end of the state, specifically San Diego is the least of places I would consider in regard to desires to find a "friendly" med marijuana area. This site has several current ongoing news articles(posts) regarding the struggles med patients are experiencing in that area and the somewhat blatant refusal by San Diego county officials to recognize the Prop215/420 laws, we as voters passed many years ago.
Hope this helps.
peace n good luck...MF