You could cut off highway 20 onto highway 530. It's a beautiful drive following a river most of the way. You'll see scenic farmland and be in a forest with trees over you like you're in a natural tunnel made of trees. Just be aware most do 5-10 mph over the speed limit but drive at a comfortable speed for yourself and let people go by when you can. Be careful in Spokane if you're not white or have some liberal or pride stickers on your car. Lotta racists and homophobes there.