When I did a route across Idaho, I took paper copies (printed on two sides) of google maps for the areas where I thought the navigation might be tricky. Otherwise, I could use a state AAA map. Also, be aware that some states, Idaho is one of them, have separate biking maps that can be very useful.

Be aware that things are not so clear when you are on the road, tired, it's dark, and there are no road signs. In those occasions, maps and even compasses are required. The nice thing about maps you print yourself is that you can throw them away when you are done with them!

For Washington, check out this site: http://www.wsdot.wa.gov/bike/default.htm . There is even a downloadable state biking map that you can use to create your route.

Ray