btw, 83miles per day is 133km per day average, which for all of my touring years, going back about 30, is a crapload of klicks per day. Waaaaaaaaay beyond my realistic level, so there you go, even in my 20s I didnt do this, and if I had, I would have screwed my knees and been knackered all the time.....
Yep ... when I was in my peak physical shape and riding 1200 km randonnees, I did a 3-month cycling tour of Australia.
My cycling partner then wanted to average 100 km/day.
We ended up averaging 80 km/day, and by the end of the 3 months, I was ready for a rest.
In our case we were trying to cycle and sightsee (because that's why I tour!) ... and if we're off on an afternoon boat tour to see crocs, or doing a hike to the top of a mountain, or taking a cruise to the Great Barrier Reef, or something, you can only fit so much cycling in.