We've descended Dosch Road many times which had us close but still unaware of this park. We entered from the south and then went west, east and finally north to an insubstantial bridge over Trillium Creek.
Wednesday, May 12, 2021
45.48066388888889, -122.70383333333334
google map 
45.481347222222226, -122.704825
45.481475, -122.70252222222223
45.48305555555556, -122.70310277777779
I met a pedestrian coming up the hill from the bridge. I asked where the trail went across the creek. "Everywhere", he said. But I think not looking at the map.
