I may sound old-fashioned, but my preferred style of moving around is - walking - but that occasionaly l did in past years up to 60 km per day. That is roughly the distance from Münster to Osnabrück.
Just would not like to do it EVERY day.
The best way to learn the mood and atmosphere and many faces of a foreign city or place. No busses. No organized tours. No car or taxi, it all simply is too fast. No bike (although that is acceptable). But walking. Ten hours, 40 km - that is realistic, saying by own experience. Just make sure you have comfortable shoes.