Welcome to the Duwamish Head Greenspace. To begin, look for the cistern which is located near the start of the trailhead. Enjoy the scenic route as you make your way through a grove of ferns. There is another non-sanctioned path to the cache from the beach side, but it would require you to cross private property and is not recommended.
Long pants and sleeves would be a good deterrent for any stinging nettles you might encounter. I'd also bring water, especially on warmer days as it's a fairly steep climb back up. The container has plenty of room should you decide to trade. Be sure to re-hide the container in it's tucked-way spot and conceal with natural camo.