Too Much in 15 days?

Mark,
I don't know if you've been this ambitious before, and if you have, I suppose you could do it. But my caveat would be that you may be on the go so much that you simply exhaust yourselves. I would skip Prague this time - a good incentive to go back, right? - and stick to Paris and Germany...have fun, and unless there's some pressing need to see this on a whirlwind, I say relax! :-)

I would go to Prague on a separate trip.

Almost invariably, if the question starts "too much" the answer is YES.

You will never see everything, but if you take the time, you will enjoy everything you see.

Using a car for the Rhein valley would do nothing but increase costs. There is very good rail transportation in the area, with rail lines running along both sides of the Rhein.

With a €27 Rheinland-Pfalz_Ticket you get unlimited on/off riding of regional trains and buses in Rheinland-Pfalz for a day (after 9 AM workdays). The Rheinland-Pfalz ticket is valid from Karlsruhe to Bonn and up the Mosel to the French border.

For a little less travel area, you can get a VRM (Verkehrsverbund-Rhein-Mosel) Gruppentageskarte for up to five people all day on regional trains and buses for €20. The Verkehrsverbund (transit district) Rhein-Mosel extends on the Rhein from Oberwesel, just below Bachaarach, to Remagen and Linz, just above Bonn and up the Mosel to Bullay.

If you REALLY want to see Prague then I would suggest flying from Paris Orly (a very nice airport) to Prague on SkyEurope. From Prague you can also fly to places like Venice or Rome on SkyEurope.

For big distances like Paris to Prague I highly recommend flying instead of driving or training.

Thanks for all the advise. However if one doesn't rent a car from Frankfurt, what is the best way to get to the Rhiene Region? Are you aware of Sixt or gemut rental car agencies in that region ? Thanks

Take the S-Bahn from Frankfurt Hbf to Mainz. There you can purchase a Rheinland-Pfalz-Ticket which will allow you (2P) to go anywhere on the Rhine.