If you live in WA state or at least backpack or hike there enough to make it worth while, you could buy the WA state software from the likes of National Geographic Topo or memory-map.com. These are USGS maps in software that you can then print out and carry with you.
They won't, however, have the particular trail that you want. Topo might allow you to download someone else's work in mapping the trail trace. That trace might be out of date in places as that particular trail has perhaps been moved a bit due to some major storm damage a few years back (?).
Green trails or USGS paper maps are expensive if you have to buy very many of them. The actual trails marked on the green trail maps are great; I prefer the 1:25,000 scale I can get on USGS maps, however, and can often find a trail trace for where I want to go. The freeware http://www.gpsbabel.org/ can be used to convert trail data that you find elsewhere into a form that your particular software can load and work with.