Interesting.
I am tentatively planning to do JOGLE next September (2020), but at a far gentler pace.
I can comfortable ride 40 miles a day on the flat, 50 on a good day, but I think that doing the same up and down mountains may be a bit harder.
Doing 70 miles a day AND a lot of climbing isn't really my idea of fun.
However if my fitness levels go up I may be able to do more.
The route I was looking at is around 1,000 miles (a minimum hill route, not one through the Lake District to see all the best views).
If I assume an average of 50 miles a day, that is short days at the start, longer days in the middle, and short days for the final hills then I was expecting to take about 20 days.
The general principle being that it is better to end the day early and energetic than late and completely worn out.
I am aware that I could average 12 mph on a good day with a following wind and no big hills, but that on a bad day with a strong head wind, rain, and some challenging hills then that could be 8 mph or less. Over 48 miles that would be 4 hours riding on a good day and 6 hours riding on a bad day. Add in rest and food stops and the day could become very long.
70 miles at 8 mph is about 9 hours riding not counting stops.
If a natural long distance pace is 15 mph, of course, then longer distances look possible.
I was originally planning to fix the route and book all the overnight stops before I set out, but I am now thinking that after the first few days I will have a better idea of how well I am coping (and also what the weather might be like) so I like the idea of booking a couple of days ahead.
As for diet, I am mainly in ketosis and cycle on just coffee, cream and butter so I don't expect to be loading up with carbohydrate but then again I'm a T2 chatting to T1s.
I am planning to ride solo, but if I am very lucky I may have a support driver to shift clothing etc. between accommodation which will allow me to concentrate on the ride and not worry so much about detailed logistics.
Who knows, I might even find I have another rider for part or all of the route.
September is still a long way away.