As someone who drives from the Tacoma-area to Port Angeles on a regular basis, the posters saying it's 104 are correct. If you use this link in Street View and face towards the 101 junction, you can see the blue signs on the right side of the road. The individual signs say:

>Foresters plant
forests anew
so future generations
will have forest, too

Last sign is STATE TRUST LANDS, managed with care (DNR?)