Hi J.,
Santa Rosa is the only Kaiser in your area that has L&D. San Rafael has an OBGYN dept for prenatal care though. Vallejo and San Francisco also have L&D if you are willing to travel that far. If you want a natural birth with a midwife, I highly recommend San Francisco Kaiser. I hear they are better as far as sticking with your birth plan (as much as you can). I have several friends who had great experiences there.
My HIGHEST recommendation however is to have a homebirth if possible! It was the best decision I have ever made and my birth was faster and smoother than all my friend's births. It was so great to just sleep in our own bed that night too! If you have not already see the documentary The Business of Being Born, you should totally rent/buy it! It's amazing!
If you need a midwife, mine was great! She has been doing it for over 20 years and has attended over 1,000 births. Her name is Diane Holzer and her # is ###-###-####. You can also Google her. My husband and I also attended an amazing birth class that made such a huge difference for us, and the woman who does those (she's also a Doula) is Susan Bradford ###-###-####.
Good luck to you!
Blessings!