Ok, not exactly what you asked for, but its in the area.

Eagle Creek Oregon? (its as close to Washington as you can get without being in it :P ) It drops into Cascade Locks at the Bridge of Gods -

I'm an east coaster and only been in the area once. But if I was every taking folks to try to hook on hiking these 10+ miles would be the place.

If you could get a drop off "up" the trail and walk all downhill into town. Waterfalls, waterfalls and more waterfalls.

What a great section of trail. I googled a link and it looks like it might have some info -