Google Maps should be taken with the whole shaker of salt...especially in the Pacific Northwest.
Almost all restricted access roads allow bicycle access up there. Olympic Peninsula, it will take you on the hiking part of the trail instead of staying on 101. It tried to take me to some non-existent trail when the Interstate was accessible. Vantage Point, you can use the interstate to cross, google tried to send me 30 miles south to cross where I couldn't. Idaho, it couldn't even give me directions.

There have been times however, I needed to hitchhike. Whittier Tunnel in Alaska for instance.