@demo_owen

The single most important thing is a protected, properly signalized crossing where Almonte meets Shoreline, with a real pedestrian phase. People walk and bike across there now and it's genuinely dangerous with summer beach traffic. Fix this first and everything else gets safer by default.

Tomales Bay oysters at Hog Island or Tomales Bay Oyster Company. Reserve weeks ahead, bring your own shucking gloves and a knife if you can, and pair with bread and a cold bottle of something dry. It is the most "you are in Marin and only in Marin" experience I can think of. Stop in Point Reyes Station on the way back for cheese and a Bovine Bakery scone.

Ferry to Angel Island from Tiburon, rent a bike at the dock, and ride the perimeter road. Five miles, one big hill, and the views shift every quarter mile — you see Sausalito, then SF, then the East Bay, then back around to the Tiburon peninsula. Picnic at the old immigration station. The ferry schedule is the constraint; check it the night before so you do not get stuck.

Point Reyes lighthouse if your visitor is ok with a long drive and a long staircase. Jan/Feb you might catch gray whales migrating; spring brings wildflowers; in fog season it is genuinely eerie in the best way. Tomales Point trail starts twenty minutes away if they are up for tule elk and a windswept ridge afterwards. Pack snacks; there is nothing out there.

Dipsea Trail from Mill Valley to Stinson Beach if your visitor is fit and game. Seven miles, three steep climbs, ends at the ocean. Catch the West Marin Stagecoach back so you do not have to walk the return. It is one of the oldest trail races in the country and walking it tells you why every step. Pack water; the climb out of Steep Ravine is no joke.

The Marin Civic Center is the only government building Frank Lloyd Wright designed and the docent-led tour on the first Wednesday of the month is genuinely great. Tell your architecture-curious friend to combine it with a walk around the lagoon. Even if they have seen FLW houses, a working courthouse with that ceiling is a different experience.

China Camp State Park is the under-promoted jewel. The historic shrimp-fishing village is preserved, the bay-side trail is gentle and shaded, the parking is free, and on a quiet Sunday it feels like nobody else got the memo. McNears Beach is right next door if your visitor wants water. The drive in along North San Pedro Road is a sneaky-good five minutes.