I did most of this route by bus in the late 2000s, mostly semi-cama style where available. Was entirely manageable mostly, apart from feeling weird as the altitude kicked up heading to Cusco, and the horrendous surface of the la paz to uyuni road. For an interminable stretch in the middle of the night in felt like we were driving over an endless washboard.
The 2008 US presidential election was on, we hadn't heard the result, the park ranger in an unbelievably remote hut at uyuni informed us that "el Moreno" had won
Funny, I was in the same area a few months earlier. Had to have a wisdom tooth pulled in Cusco and then had a dry socket in Uyuni which was agony.