I have two friends from my class that are out in SD. However, they did take Step 1 and went through the ACGME match. In talking with them, it's not that SD isn't DO friendly, it's just that they don't have any AOA residencies. They didn't feel like they were treated any differently because they were DOs. I would advise doing a rotation out there which I think would greatly help your case. That's in part, I think how my friends ended out there; they made some connections and got letters from those programs' residency directors. They applied to several places knowing that Cali is hard to break into especially if you are coming in from the outside but I think doing well in school, taking Step 1 and applying via ACGME is the way to go.
On a personal note, I have spent quite some time out in California and have seen a A TON of DOs practicing out there. Much of SoCal specifically is into integrative and/or holistic medicine and so everyone out there is practicing some form of alternative medicine including OMM, acupuncture, reiki...etc. So I would definitely encourage you to take a chance and try to get out there for residency. You may just have to do some extra work!