Given that much of my trip will be by car, I will need to maximize sightseeing in remote rural places where trains are not as convenient, and stick to big cities only when I am not driving. Also, all the territory to be covered in this trip, with the exception of Paris, is brand-new to me, so I have a lot to look forward to, but proper planning is crucial.
The first four nights are set in stone now with firm reservations. I will fly to Munich and stay there for two nights. I have one and a half days in Munich, but the full day will be Sunday (shops closed) and the half day will be Monday (museums closed). I'll stick to the parks/gardens and a museum on Sunday, then walk around some downtown sights Monday, before heading for Stuttgart for two more nights. The hop to Stuttgart will use a train; there are very frequent train runs, mostly of IC and ICE grades (though the ICE isn't fast on this line).
The full day in Stuttgart will involve the delivery of my folks' Mercedes-Benz, and a visit to the Mercedes-Benz Museum, but I will also make sure to devote some time to the city's scenic downtown.
After those four nights, my plans are still in flux, though I have a rudimentary outline. I'll drive portions of the Romantic Road with a stop at Rothenburg, and will probably overnight at Fussen, next to Mad King Ludwig's fantasy castles. I am also looking at overnighting in Salzburg, Austria, and another fine Austrian town, Innsbruck, will be a brief stop. Venice will be my lovely Italian introduction (I hope the large garage at the island city's entrance will be safe), and if driving conditions are not too bad, I will squeeze in a bit of Switzerland, primarily Interlaken but maybe Zurich. I won't go deeper into Italy given Italy's high car theft rates and the expense of the car (even riskier given the car's tourist plates).
I will return to Stuttgart, after a week on the road, to ship the Mercedes to the US, then hop on a French TGV for a relatively fast hop to Paris, using a new high-speed line from Strasbourg. I am devoting three full days to Paris, which I insisted on, not for myself (this is my third Paris visit), but for my mother (her first European visit). I will revisit most major sights, but will try to find a new, unique Paris experience.
My US return will be fourteen days after my initial Munich arrival. Out of Paris' Charles de Gaulle Airport, I am booked on a Lufthansa flight backtracking to Munich, where I will then catch a Los Angeles-bound flight.
The rest of the planning will be at least as fun as the trip itself. But I need to make sure to build some flexibility in. Some sights may be duds, others may be gems requiring more time. Will see what I end up with.