Usk WA to Sandpoint ID (USA) route advice sought

On this summer's unsupported tour, we'll be riding from the bustling
metropolis of Usk (in Washington State) to Sandpoint Idaho. We could
go on the south side of the river, or the north side. Newport WA is a
likely lunch spot for us, so we can cross the river there as needed.
Which is the better route?

Using Google street view (what a resource! OMG!) I can see that US 2
has pretty decent shoulders from Newport to Sandpoint. Old Priest
River Road on the south side is not visible with street view. And both
sides of the river - Hwy 20 or LeClerc Road - from Usk to Newport are
not on Google street view either.

Do you have tires-on-the-road experience with either route?

Claire Petersky

http://www.bicyclemeditations.org