I once had a talk with an experienced cycle tour guide, he was in fantastic shape as his job was riding. He rode 100 miles every other day. Didn't matter what the trip that day was, he made sure he got the century done on his ride days. The other days it was his turn to ride in the truck. With that schedule he confided in me that after a month he was too worn out to keep it up. This was a 30 something very fit cyclists riding with out gear (Supported tour) If he couldn't keep up 100 miles a day every other, I think most folk would not be capable of 100-150 every day. I've been riding one way or another for 30 years on a regular basis. I average about 70-80 miles per day on tour, some days I do 100+ some days I do 50.

I'm not saying it can't be done, I know it has been, I'm just saying most folk cannot hold that kind of mileage.