I thought I would give a suggestion of a different way for exploring the Palouse region of eastern Washington. Cycling can be a great way to see some of the beautiful landscape.
Some of the positive aspects of traveling this region by bike would be the well paved roads with very little traffic. In addition you are going at a pace where you can really take in the scenery. The exercise in the clear fresh air is another aspect that makes this mode of transportation enjoyable. I however would caution that you are prepared for the elements as the temperature can soar to very high extremes especially in the summer months. Make sure you have plenty of water and food with you as the towns are few and far between in some areas.
I was an avid cyclist for many years and have ridden thousands of miles in this area. So from experience I can assure you that cycling is a very good way to explore, view and enjoy the Palouse landscape.