Bessa R or one of the Leica Screw mount competitors like a Canon P or L is a good start to a system with an endless choice of lenses.
If you want to try a good and extremely manual camera that you can actually repair while backpacking there is the Argus C-3. The viewfinder is bad, the shutter only goes to 1/300th, and not even shutter cocking is automatic, but the lens is very good and you can get one for less than $20. If you tell people you really like old cameras someone will eventually probably just give you one.
As for portability, and a good viewfinder, the Retinas are hard to beat.