Canvas the neighborhood and note which properties do not have 911 signs. Contact those neighbors and alert them to the code requirements and urge them to comply.
If you are able, help your neighbors to install those signs, or ask the Boy Scouts or some organization to do so.
Understand the area within which you live, its vulnerabilities, best way in and out. Then socialize that information to your neighbors through Next Door or through your local email groups.
Get more of the neighborhood involved through Next Door, Facebook, local email groups.
If you live within a Fire Safe Council (FSC), make your neighbors aware of it.
Make a neighborhood phone/email tree.
Identify which neighbors might need assistance in evacuating.
Identify block leaders and have them monitor Napa County Fire Department frequency.