Opa sez:

 Maybe take it all the way to Ontario and wander down the Snake River
through Hells Canyon.

oooooooooooooooooooooooooooooooooo

You can only ride about 25 miles or so along the snake in Hells Canyon
before the road dead ends at the dam. Only a few stretches of straight
road  longer than  a hundred yards on the route though. Lots of curves,
and sand and debris on the center when I rode it a couple of years back.
The scenery is nice, lots of boats and bikinis anchored near the banks.
I don't remember any gas stations once you head up the canyon.

Skinny Kenny