The map can be very misleading. You have to get on Coastal Trail first, then on to the cache while on the trail. Do not try to get to it directly from the street or park above/east of the cache as that would be a Terrain = 5. The easiest access is from the Parking Waypoint at Elderberry Park and the Oscar Anderson Museum just south of the cache.
Ground zero has several interesting features once you start looking closely. Please be careful and do not damage any of them in your search. You are looking for a small-size cache, but it has to be well-camouflaged to hide from muggles on this busy trail. While you are searching, don't block the whole trail pathway as cyclist, runners, skiers, and all other forms of pedestrians come by day and night. The cache is not in the railroad right-of-way or on private property, even if your GPSr points you there for a few minutes.