States: California: Shasta
My info stops at December 31, 1880. I don't live near Shasta County and my mother's book is really the only research tool I have about it; but do check the Shasta County GenWeb pages for other lookup volunteers; also there are some resources on a website belonging to a Janie Edwards; there is (or was, last I knew) a link to Janie's pages from the Shasta County GenWeb site. You might be surprised at what is there.
Also, since your aunt was born about 1900, try the California birth records online via Rootsweb.com. You can search by her maiden name (Ward?) and husband's surname (Trueblood?) and see if they had any children born in California. The database covers 1905-1995.