Stephen Partington
Google
Note: The pictures are not from Olympic Peninsula, but Tasmania's UNESCO heritage area: for comparison.
I lived in nearby Sequim 20 years ago when National Park access was restricted to perimeter roads. Even today many mountainous areas are inaccessible by any means.
Olympic Peninsula reminds me of the Tasmanian Wilderness World Heritage Area https://g.co/kgs/YsxJscP, where I've been the past few days. Most is impenetrable, except by boat along the Gordon River: eg, with World Heritage Cruises based in Strahan. The World Heritage Area has one access road to the coast in 15,800 square kilometres. That's 4 times the size of the Olympic Peninsula NP.
FOR COMPARISON.. You can see the likeness in the attached photos along the Gordon River and Dove Lake at the foot of Cradle Mountain.