Last century I regularly rode 125 to 150 miles a day and thought nothing of it. (I was much younger and stronger in the 1970's)
Now days I will ride my '08 RE Thumper ("Old Bill") every day fifty miles commute (each way) to and from work. I keep to the two lane roads where I can and hold my speed around 55, or sixty at the most. I quickly got rid of the stock bench seat and installed the least expensive of the CMW solo saddles.
The fifty mile ride is quite comfortable. "Old Bill" regularly drinks faster than eighty miles per gallon of 87 octane "Regular" gasoline.
I did take one 325 mile trip with a friend this past summer. I rode "Old Bill" while he was riding his brand new Harley Davidson twelve hundred (that number might be a reference to the weight of the machine, or maybe it was the displacement of the engine?
) On some of the mountain roads going up the Cumberland Plateau, he was struggling, fighting his bike, while "Old Bill" twisted and carved the road like a real Motorcycle should.
I thoroughly enjoyed the run, although the next morning I did reinstall my windshield and have kept it on.