Updated: May 17, 2021
I'd never have stumbled upon CA-139 if it weren't for my idiot navigator, coincidentally named Bob. His ability to read a map, particularly on a phone not running the app is suspect. Still, he works cheap as a package deal with the other personalities.
CA-139 connects CA 299 and the bustling metropolis of Susanville (pop17000) where I had the second best pozole of my weekend. Point is you'd scarce have a reason to be there unless you hired my navigator (which I would not recommend).
That said, it's a fabulous drive.