Nice little trail to explore if you have an hour plus wait to catch your ferry (or if you make this a little trip while on the island and park in one of the ferry lots while hiking.)
The trailhead is right off Ferry Road on the left side as you are approaching the ferry staging lanes. It is directly across the lanes from the southern end of the upper ferry parking lot. There is a small sign telling you it's there and then you will see the map after leveling off the trail going up the hill.

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