Use Google maps. It takes you directly to the light house. You might also consider downloading the map for that area.
High way 101 goes through Pt.Reyes, and then through Inverness out to the end of the peninsula, where the famous lighthouse stands... There are laguns and beaches all the way out, but only Drake's beach at the end there which is much colder than, say, Heart's Desire.... A food stand there though...
Use Google Maps (don't ever use Apple Maps)
Google maps...some mobile carriers no service..be prepared
I recommend Google maps 😉
Its a highway that takes straight in to petaluma
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