May be jd, you can introduce yourself.
I've only known 2 people who have done over 200 km in 1 day: My partner which he pulled in 210 km. in 1 day in the midst of a 3 month long ride across North America --solo. On that day, he was riding through Canada's desert @ 25-20 degrees C heat.Day 1 is 203km, day 2 is 156km, and day 3 is 218km.
So he was riding with his gear. He did ride across Canada in 45 days, averaging 100 km.... from Vancouver to Toronto. It was an enormous feat for my dearie....to ride 90% of the days, daily @ 100 km. minimum or more. He was 58 yrs. old when he did this.
My partner has cycled now, probably 115,000 km. over last 20 years because he's done some major bike tours (lots solo) and because we're car-free, therefore cycling is our transportation.
the other person is Mimitabby's husband who was a randonneur before he had surgery on his cancer. Even my partner was in awe of her hubby, in terms of his occasional 200+ km. rides.