Very helpful. Your cousin has family knowledge that Mary did not grow up in California. Good to know, and thanks for sharing that, because I did not yet find any record that would be "right" for that story.
You write: "It is worth noting that several of the children made it to CA, not just Mary, but David, and John. I think that Benjamin might have as well."
We've posted quite a lot about John being in California. Just prior to you writing this, I posted a record for Joseph being in California. Did not find Benjamin there; I did look.