The Presidio is rumoured to be federal land, and I'm wondering how that affects what law is applicable there. Does California law have any effect there?
Only a partial answer as I (and maybe others) attempt further research...
... carries out its responsibilities in parks and programs under the authority of Federal laws, regulations, and Executive Orders, and in accord with policies established by the Director of the National Park Service and the Secretary of the Interior. (Source: NPS)
As a general principle, state or local governments may not directly enforce their laws against the National Park Service with respect to federal lands and activities within units of the National Park System. This principle originates in the U.S. Constitution.
Article IV of the U.S. Constitution outlines the relationship between the states and the Federal Government, and each state and the others.
Article IV, Section 3, Clause 2, known as the Property Clause, grants Congress:
Power to dispose of and make all needful Rules and Regulations respecting the Territory or other Property belonging to the United States….
This delegation of authority to Congress over federal lands, and the re-delegation of that authority to the various land management agencies, prevents states from enforcing their laws and regulations that pertain to lands, such as zoning, building permits, and land use regulations. (Source: NPS Applicability of State and Local Laws to NPS Activities pdf)