Anybody know if its practical to travel Europe via its rivers? I'm referring to independent travel, not formal cruises. Not renting barges, etc. Just hopping on and off public boats as one might hop on and off the train.

It's possible, but obviously you can't just go anywhere you want. And just as obviously, you'll have some land travel between rivers. There are boats that cruise all of the larger rivers in Europe (for instance, Rhine, Mosel, Danube, Rhone, Seine, etc) but constructing an efficient itinerary would take some time for you to do. If you have the time to plan and the time to make this kind of leisurely trip, it would probably be very enjoyable. Good luck.

There is a regular service from May onward (I believe) between Vienna, Bratislava and Budapest -- three capitals in a day.

BTW: An interesting factoid: The downstream trip on the Danube is Vienna - Budapest: the Danube is the only major river in Europe that flows eastward.

Oh did I mention it is a hydrofoil (I think) rather than a boat???

Tedgale:

For shame.

It may be shorter than the Rhine. It may once even have been a Rhine tributary. But many of us think the Thames is pretty major.

And what about all those enormous things that begin with Dn? Doesn'tthe Dniester, for example, flow east?

Apparently the only thing that some people think of as "major" in the UK right now is the "happy couple."

Any major rivers, other than the Rhine, that flow North?

The Elbe, the Seine, the Garonne, the Vistula.