Hi sliceoflife,
Subject to confirming that any retailer or manufacturer on the list is completely transparent (see this article) and to making sure that any mattress you are considering meets your specific criteria and the quality/value guidelines here … the better options or possibilities I’m aware of in and around the San Francisco/San Rafael/Oakland/Berkeley areas are listed in post #2 here.
Going south the list for the San Jose/Santa Cruz/Salinas/Monterey areas is in post #2 here and for the Bakersfield area is in post #2 here and for the San Luis Obispo area is in post #2 here and for the Santa Barbara/Ventura area is in post #2 here and for the Greater Los Angeles region is in post #2 here.
Hopefully that will cover most of the areas you go through when you travel south but there are certainly some very good options available in the SF area.
Phoenix