I have the 1880 cenus on cd from LDS, however they have that
census on their web site
Also, if you write to the county of San Francisco attempting
to get a death certificate, I am sure they will give you
information they require or where you can direct your inquiry
to get a certificate.
You might try to see if San Francisco, has a separate web site,
a lot of major cities do. Sometimes they have sections on
genealogy(as do some states)
In addition, you might try www.usgenweb.com, and you can further
narrow your search to the county San Francisco is in.