Before you consider moving to California, you might want to take serious consideration of the fianancial aspects.
I'm from the OH/PA border originally. My work to me to SoCal. I had to live in the Low Desert area of Riverside County to afford to keep my horses -- which were on my own property. I only had 1-3/4 acres and folks out there thought I was rich and considered my place a "ranch" !
Unless the Rules Have Changed:
1. There's a Smog Impact Fee when bringing vehicles from another state into California.
2. Your license plate fees are based on the blue book value of your vehicle. Soooo, if that big honkin' dually that faithfully pulled your horses cross-country, happens to be Blue Book valued at $40,000, you're going to pay a percent of that 40K for tags.
3. Depending where you settle, Earthquake insurance may or may not be required. It ain't cheap - I wasn't required to buy it but had I done so, the cheapest I could afford would've cost $1,200/annually (in addition to standard home owners) and the deductible was $35,000! What's the point in the coverage if I have to pay the first $35,000?
As far as horse feed, vets, farriers, WalMart, Lowe's, and the grocery store, the prices variance from where I lived was barely noticeable.
But any sport you want to dabble in (including horses and boarding them) is priced into the outer Stratosphere.
There's always the chance water restrictions may become an issue in Southern California since they depend on Northern California for the bulk of their water.
Don't forget that California is nearly bankrupt and I would look for their state governement to start heavily taxing the working folk to help bail them out.
If you want dry, the only place west of the Mississippi I was considering when leaving SoCal, was the Mogollon Rim in Arizona (pronounced Moog-ee-own).
Then I decided I really wasn't cut out for dry and no grass, and headed to Middle Tennessee for retirement. It's a lot cheaper to live here and plenty of place to ride. RFDTV's "America By Horseback visited the Circle E Guest Ranch, which is only 38 miles from me.
I came to hate Southern California; I'm sure my outlook would've been a lot different had I not had the horses to care for.
Good luck in your decisions :)