Buncha comments on your story:

1. That's not the most popular kayaking stretch on the upper Salmon.
Most popular would be the Sunbeam run downstream, where you would
have had an easier time locating other paddlers.

2. I recommend hitchhiking with PFD (sans knife) not paddle, which is
cumbersome. That's a fast stretch of highway. Personally I prefer
bicycle shuttle to hitchhiking.

3. The Amaral guidebook says the scenery on that stretch is great!
Hope you had time to enjoy it.

4. Boating alone. Lots to be said about boating alone.