A few weeks ago I made a 150 mile round trip over a weekend. The road was almost perfectly flat, but the trip up was hampered by constant 20mph headwinds with gusts up to 30. I had already planned to make regular stops, but I had to stop even more often to re-fuel myself. The trip up took about 10 hours, including stopping for food and rest, catching a ferry, and a mechanical problem.

The return trip the next day was about 7-8 hours because I had a tailwind pushing me for part of the way.

Except for the times I was struggling up some short, steep hills into the wind, I was basically cruising and looking at the scenery.

A couple weeks later I did 100 miles on a crushed rock bike trail in 8.5 hours. But towards the end I wasn't enjoying it too much. It was more a test of endurance and my willingness to inhale rock dust.

I think the idea is to enjoy yourself. If 50 miles a day will allow you to have fun, then that's what you should do. If you need to do less to enjoy yourself, then do less.