We drove Amsterdam - Prague a year and a half ago. Not sure offhand where Frankfurt fits in there on the map. We rented online through EuropeCar, I think it was, based in New England. That was the only way we could find to get a rental we could take into CZ.

We picked up the car from one of the big name outfits at Schipol who balked about is taking it into CZ but were OK when we pointed out who we make the res through. Make sure your rental papers explicitly say you can to into CZ or you may have problems at the border.

We enjoyed the trip greatly, but took our time. Not sure if it would be as much fun in such a rush. An overnight stop in Plzn (Pilsen) and tour of the Pilsner Urquell brewery was a real highlight. Bought a big Michelin spiral bound map book along the autobhan and it was a lifesaver.

There is a border checkpoint, and you have to buy a road toll sticker for your windshield. Our stops in Czesky Krumlov, Karlovy Vary and Plzn were great, as was the stunning castle at Konopište.

Hope you can find a bit more time.