I would say 1 max 2 hrs would be more than enough. It's rather a small museum
It is a small museum so not too long....leave time for the walk around the point
From the museum, walk towards the ocean and turn right and walk up the paved trail. This is called Heisler Park, and the best scenery on this part of the coast. For a good place to eat, next to the museum is Las Brisas or immediately across the PCH, go to Urth Cafe which is great for food, coffee, or dessert.
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