https://www.atlasobscura.com/places/camp-hayden-abandoned-ww...
Triangle of Fire - The Harbor Defenses of Puget Sound (1897-1953): https://www.historylink.org/file/7524
Fort Worden State Park in Port Townsend is the one I'd recommend visiting if you could only see one.
https://www.atlasobscura.com/places/camp-hayden-abandoned-ww...