I will be traveling to Germany for about 2 weeks with my gf. I will spend an additional week out in Europe to visit Normandy afterward. I have most of my itinerary planned out but would like to get some advice for some of the free time/gaps I have, as well as some advice for booking a rental car.

So far, my itinerary is:
4/28/2010 - Depart San Francisco
4/29/2010 - Arrive Munich
4/30/2010 - Munich
5/01/2010 - Munich (day trip to Dachau)
5/02/2010 - Salzburg (morning drive from Munich to Salzburg, sightseeing afternoon)
5/03/2010 - Salzburg (day trip to Berchesgarten)
5/04/2010 - Fussen (Drive along Alpine Road from Salzburg to Fussen)
5/05/2010 - Fussen (day trip to King's castles)
5/06/2010 - Rothenburg (morning drive from Fussen to Rothenburg, sightseeing afternoon)
5/07/2010 - Rothenburg
5/08/2010 - Rothenburg (Wurzburg/Bamburg/Nuremburg)
5/09/2010 - Rhine (morning drive to Bacharach)
5/10/2010 - Rhine
5/11/2010 - Rhine (possible day trip to Trier/Cologne)
5/12/2010 - ? (GF departs home from FRA in morning)
5/13/2010 - ?
5/14/2010 - ?
5/15/2010 - ?
5/16/2010 - ?
5/17/2010 - Full day Normandy tour
5/18/2010 - Full day Normandy tour
5/19/2010 - ?
5/20/2010 - ?
5/21/2010 - Full day Normandy tour
5/22/2010 - Depart Paris (CDG)

After my GF leaves, I would like to go see Luxembourg and possibly back to Brussels (only did a day trip from Brugges last time I was there) maybe for a day or two, also to visit some WWII sites. Any other ideas/places around this area that I might be forgetting about?

As for the rental car, we plan on picking it at the end of the Munich trip as I don't think we'll be needing it within Munich. We plan on driving in between all the cities from Salzburg all the way to Frankfurt. I haven't decided if I should keep driving on my own all the way to Normandy after my GF leaves or if I should just start taking the train.

Suggestions;

Stop in Dinkelsbuehl on the way to R od T

You cannot do Wurzburg, Bamberg and Nuernberg in 1 day. I am wondering if you meant that you would select one of them? If you have to choose, I bet Bamberg wins the votes in here, especially if you like beer........

For the Rhine days, Trier would probably be a better option than Cologne. Try and spend some time on the Mosel on your way there, or back.

From FRA you could stay in the area for a few days (Wurzburg?) or start heading to Normandy. Through Paris seems the most logical, but for a guy who just dropped off his girlfriend, maybe not.... You could go south a little - and this presume you are driving to Caen - through Strasbourg and then cut up through the Loire valley, about a 12 hour trip. Or, you could head to Brugge and then come down through some more WW1 and WW2 sites in Belgium and France like Ypres, Dunkirk, etc.. That would be about 9 -10 hours driving.

Dropping the car in France could prove expensive - do check it out though because it would make visiting WWI and II sites much easier and that seems to interest you.

If you are taking the train, the going to Brussels and day trippng in Belgium before heading to Caen makes some sense, too.

A rental drop in another country will be expensive, so you may want to check on the price of that. But, having a car would be nice. OTOH, you might want to think of just taking a train into France and picking up a separate rental there. A bit of a hassle but might be a money saver.

Bamburg is no where near enough to Rothenburg to do a day trip to there and Wurzburg. All you would be doing is driving non-stop. We weren't all than enamoured of Rothenburg and much preferred some of the smaller, less touristed, authentic towns in the area. We only had one night in Babmurg and definitely wished we'd had more. I second the thought of the Moselle area. If you life active trips you can rent bikes and cycle along the river.

"Bamburg" does not exist anyway, the city is named Bamberg.

I hope you are not planning to see Bamberg, Würzburg and Nürnberg within one day? This won't work, and it would be a shame to just race past them. Each of them deserves at least one day. Since you have several days to fill, devote more time to these 3 and the surrounding region, like Franconian Switzerland, the wine villages in the Main valley, Bayreuth, Kulmbach and Coburg, the palaces of Veitshöchheim and Pommersfelden... There is enough in that area to fill a week. Apart from that, the region is famous for excellent wine and beer.

Thanks for your advice guys/gals.

Sorry I did not mean to say that we will be visiting Wurzburg, Bamberg and Nurnberg all in one day. They're the 3 options I've chosen to do a day trip. I'm leaning more towards Nurnberg for its WWII significance but am considering Bamberg too for its charm. I will probably save Wurzburg as a separate day trip on my own once I drop the GF off at Frankfurt airport.

I suspected dropping a rental car in a different country would cost more, but I brought it up anyways in case there were alternative ideas to the rental car. Rick Steves suggests leasing as a cheaper alternative if renting for 2-3 weeks at a time. However, leasing doesn't appear to be as cheap as renting to me so I'm not sure if I'm missing out on some other type of "leases" out there.