If you need to your residency in California then you'd be better off going to a Californian osteopathic school. How much does it help? I'm not sure but I genuinely do believe it matters.
I know someone who went to a DO school on the east coast. Then they did their residency at a decent state program on the east coast. Then they did their fellowship at a good place in the Midwest. Now they're an attending in LA. I guess my point is: you can always move west (or east) after your training, especially if you do your training at reputable places.
I do think it's hard to match residency in a "desirable" city as a DO if your school is not located in that area. I'm pretty much just thinking of nyc and California.
Washington and Oregon were not DO friendly places when I was applying for residency in 2013, but I got an II at university of Washington for residency and fellowship, and I'm coming from the east coast. Didn't hear anything from Oregon ever.