I've biked past here many times but it wasn't until I parked nearby as an employee to replace a log of a nearby cache I adopted that I found a trailhead into this beautiful area. Microsoft has constructed a very nice boardwalk and crushed gravel walkway complete with signage to teach you about this marvelous places where nature flourishes.
There is no reason to leave the walkway and you should not disturb this ecosystem.
You will come to an amphitheatre about midway from either trailhead and the cache is easily found on that grassy area. My Garmin has this listed as a picnic area and while there are no tables, the benches might suffice for a beautiful picnic to be sure.