A national monument where you can forest bathe as you stroll along curated paths set among old growth coast redwoods. Reservations are required for both parking and shuttle service (the roads to Muir Woods are winding and a bit hectic, so you may want to consider whether you are happier navigating them yourself in a car or in a large bus). More information about reservations is at: gomuirwoods.com.
We love oysters! If you have extra time, the Hog Island Oyster Farm in Marshall is about an hour drive each way from Larkspur and offers farm tours and has a fun outdoor oyster bar. If time doesn't permit a visit to the mothership, we are lucky to have a Hog Island Oyster Restaurant in Larkspur at the Marin Country Mart offering their delicious oysters and other seafood (Brad is a big fan of the chowder).
If you are looking for a little pampering, International Orange in the Marin Country Mart is one of Steph's favorites for massages and facials. If this interests you, be sure to book ahead because their scheduling is usually tight.