You should consider looking into a bike & barge trip. My parents have done a couple put together by a ski club that they’re a part of, and it sounds like the kind of trip that you’re talking about, only you wake up in a new place every day and bike ride to meet the barge further upriver at the end of the day. I know they do them in and out of Amsterdam, but my parents did one in the Loire River Valley and absolutely loved it.