There used to be some feedstores that would carry it or order it. Now, it's really hard to say if any of them would have it around anymore. The chain stores wouldn't have it for sure, they go with the smaller, prepackaged in nice pretty containers or packets type.
Don't be scared of ordering online...especially the dust, you will save a ton of money over buying at the petstores.
Speaking of...Susan (AZChins) carries Blue Cloud and if my memory is working right, she'll sell you a flat rate box full at a reasonable price. She also has a lot of the other essentials you'll need.
I'm in AZ...so if anyone needs any, I can get it to you cheap. I offer free delivery to Tucson and Phoenix when I am going up to those places anyway.
They still have feedstores with it in CA? That's great. No one here can order it anymore for some reason. Do ranchers normally sell their dust to local people? I didn't know that! That would be really helpful for people not wanting to pay for shipping...if the ranchers want to let people pick up things from them, that is.