suze

Hmmmm (I'm no expert but) I'd get my hotel(s) booked, especially in Paris, as the first thing on your to-do list. Once you are in Paris your hotel front desk may be able to help with your other questions. Or check the library or bookstore for guidebooks to figure out the smaller details. You can most likely purchase your tickets in person at any train station. Ask your friends in Munchen to recommend a hotel. Take taxi(s) from and to the airport, unless your hotel can suggest a shuttle.

Mary_Fran

Maybe too late, but I'm up with insomnia, so here goes anyway.

I'd rearrange your itinerary just a bit and add the estimated travel times:

21-May arrive in paris
22-May Museums
23-May Paris sites
24-May Day trip to Reims (1.5 hrs each way)
25-May Train to Caen (2 hrs), D-Day stuff, sleep in Caen or Bayeux
26-May Train to Dijon (4.5 hrs)
27-May Dijon wine tasting
28-May Train to Luzern (4-5 hrs)
29-May Luzern
30-May Train to Munich from Luzern (5.5 hrs)
31-May to 2-Jun, Munich
3-Jun Drive from Munich to Stuttgart (2.5 hrs)
4-Jun Drive to Baden Baden (1.25 mins)
5-Jun Drive to Strasbourg (45 mins)
6-Jun Drive to Freiburg (60 mins)
7-Jul Train to Frankfurt (2.5 hrs)
8-Jul Fly out

For the last three days before leaving for Frankfurt, do you plan to use one of the three towns as a home base? They're very close.