Hi John, Harriet died in San Mateo County which can be anywhere in the County. The county is very large with MANY towns and cities so finding an obituary is difficult. Also there are no obituary volunteers for this county.
First I'd check Legacy, legacy.com/obituaries/mercurynews/ . There is no fee to see if they have her obituary and a nominal fee if they do have it.
You can access the SiliconValley Library System Reference Center's web site, http://obit.systemref.orghttp://obit.systemref.org. Fill out the form and they charge a fee to search.
You can contact the Santa Clara County Historical & Genealogical Society, scchgs.org/main/service.html who charges a fee to search.
You can order a copy of her death certificate which might contain the town or city where she died and where she was buried. Successful Searching!