"...spend a few days near Ramstein AFB
then drive to Neuschwanstein Castle drive
drive Luzern
drop the car off and take a train to Paris for 3 days..."
Seriously? Sounds like you just want a long drive, which is fine, I guess. When is this trip? How many days from Ramstein until you leave Luzern? If I were driving around 1,000 km (which it sounds like you plan to do) I would want at least 4-5 days for this so that I had time to see a few things from somewhere besides the front seat. If you drove Ramstein - Luzern (which I know is not your plan) that's 400 km right there Then you'll want to drive back into Germany to drop the car (to avoid extreme foreign drop off fees) so probably Offenburg (add 200+ km) so you can catch the train to Paris. So 600+ km. Adding Neuschwanstein (NOT a castle but a late 19th-century palace with a faux castle exterior) adds a 300+ km detour (for a 30-minute tour??)
If you want Alps and your time is limited, then I would absolutely skip N'stein and the extra driving kms and head straight from Ramstein into Switzerland, where the Alps will be more impressive. (I would squeeze in a visit to the Bernese Oberland too if you have the time.) If you want to squeeze in one of Europe's coolest and most impressive palaces, make a stop on the drive south from Ramstein in Ludwigsburg, a place with some serious history behind it, near Stuttgart.
If you want a castle, then spend some extra time on the Rhine. Marksburg Castle, one of 40 real knights' castles on the Middle Rhine, is "unchanged from medieval times" and open year-round for tours. It's in the adorable town of BRAUBACH.
Hotels in Luzern