There are some places on the upper river where you could dock a boat and camp on public lands.
In the #'s you have Miner's Campground and Railroad Bridge.
In Fractions you could camp below the highway at the 1/2 way fishing access, or Elephant Rock.
I don't believe there is any public lands to camp on from BV to Ruby Mountain, but you can camp at Ruby.
There are multiple campsites on the way into and through Brown's.
I have seen people camped once between Big Bend and Salida, but public and private lands are not well marked.
Salida East and most of the river left side down to Rincon as well as Rincon itself.
Vallie Bridge has developed river-side campsites.
There is a really nice flood-plain on river left below Texas Creek that I have seen boaters camped on.
There is camping on the other side of the highway at 5-points.
You could camp at the river right "Maytag" access point between Texas Creek and Pinnacle Rock.
That's about all I can think of, but should be plenty.