This one is especially interesting. For the home of Petulia and David Danner director Lester combined two separate locations several miles apart and even duplicated one of the structures to achieve continuity between the sites. Below, Archie visits the home and we see him arriving at the carport.
Then ... The carport has a lovely cross-bay view to Sausalito and the Golden Gate Bridge, probably why this location was chosen.
Then ... In a later scene Petulia and her young Mexican friend Oliver exit the house and approach her Rolls-Royce parked in the carport (the entrance gate, below, can also be seen at the far right of the movie capture above).
... on location ... The cast and crew are seen in the carport during the filming of the scene.
Then ... In the movie the carport connects down the hillside to the house by way of a funicular platform. Below is a view of the house from the bottom end of the funicular ...
... and Now, but this house is located miles away, across the bay from the carport! CitySleuth is refraining from giving the actual street address from owner privacy considerations but a Google satellite view of the house is shown below. It is one of four homes in a private 38 acre estate on Paradise Drive in Tiburon, overlooking Keil Cove (map). (Clearly then, the car port at the top of the funicular duplicated, for locational continuity, the real carport across the bay. It's a funicular to nowhere!).
Then ... Several scenes at the home were used throughout the movie. Below, David enjoys the pool while Petulia takes his picture. The pool is clearly visible at the rear of the house in the Now photo above.
Then ... In another scene (below) the house is viewed from the beach at Keil Cove, perched above a lake. The small pier and gazebo were built for the movie by the Warner Brothers studio.