Sassthe1, I used to live in California. If I decided to homestead in California, I would start by looking at what you HAVE!
Do you have any back yard at all? You can raise SOMETHING year-round in most of California. You plant, raise the veggies for 3 months, then harvest for 6 months. In addition to that, it is possible to raise greens most of the winter. Veggie tops can be put into bins to compost and raise worms. Chickens and rabbits may be possible.
Out here, (excepting for greens), you plant, raise the veggies for 3 months, but then only get to harvest for a couple of months before it gets too cold for the tomatos and cukes and such. I have the Californians love of fresh food, so I find that I buy salad greens except in spring and fall, and tomatos and such in the winter and early summer.
The point of this is, 100 square feet in California CAN be as productive as 300 square feet in Kansas. If you have a yard at all, think about that.
If you DON'T have a yard, then I would do a google search on united country to see where the affordable land in your area is. I have found that if United Country has a listing in an area, there will be other similarly priced lots in that area.