I believe that most cyclists take on the day at the very beginning. Sunrise maybe? But has anyone ever tried doing their ride in the evening? Instead of cycling in the morning, ride your 70ish miles in the evening as the day gets cooler and arrive at your destination just before sunset? I know there are the obvious (having time to fix problems while it is still early) but aside from needing time to fix problems with the day coming to a close, is there any reason NOT to do your miles after lunch?
If you don't have overnight reservations, you can't count on finding a place - unreserved places are generally more available earlier in the day.
Fully loaded, I find it takes us 7 hours of riding to do 70 miles, including minimal breaks. Unless we have a tailwind.
Add to that any reasonable break time, and you're looking at 8-9 hours. If you're far enough north and it's close to the summer solstice, this could mean starting out as late as 2 PM: the HOTTEST part of the day. If the heat is unusually bad, we'll normally do part of the distance in the morning, and then take a break, to possibly include a nap, through the mid-afternoon portion, when the heat is worst.
On a recent trip we did start one short day around 2 and by 5:30 it felt like we'd been going since at least 10. It was uphill, upwind, and hot, which explains part of it. But those morning hours that we weren't riding we were using up some of our day's energy. When on tour, the base metabolic rate goes up, so we were burning way more calories in the morning than seemed normal. It's just easier to ride when you're relatively fresh.