Yikes is right!
I did decide to "follow" the road down a bit on Street View, to try to get some perspective. Is it really as narrow as it looks? And I found a spot where the Google car showed an approaching car, and there is definitely room for two CARS to pass.
Two motorhomes or a truck and a motorhome would be a different story, however. And I sure wouldn't want to be the one who had to back up!
I think we'll get our views of the Palouse elsewhere. Thanks.