Vacation planning help

Hi,

first off, for car renting, you should check you have the right to use it across several countries (as non-resident of any of these countries, it should be easier but still worth a look).
The whole area is very nice, there are many nice lakes, it depends how far you want to go.
Lake Geneva is very nice, with plenty of luxurious hotels, as well as lake neuchatel and lake de Fribourg.
In the south, with the italian border, Lake de Garda, Lake de Como are all worth a visit (try villa feltrinelli for the greatest rooms available -in the world- but a price...)
Lake Zurich is very nice as well, but doesn't have so many luxury hotels, there is also lake de constance, with a nice "tropical" island in the middle (at the german border).
I would say at typical tour would be :
either landing in Munich (LH/United fly there direct from LAX) or in ZRH (Swiss/AA fly direct from LAX as well), so you're not too far from "the action",
berchestgarden etc. you could take a drive via austria, go to Switzerland and then back to Germany, via Frankfurt for example (and try out a bit more the autobahns), usually you can find pretty great deals in germany for renting Porsches at a very decent price from major rental companies.
As a general rule :
Bayern and germany have really great castles (if you ever wondered where disney got inspiration for their castle, try schloss Neuschwanstein...and it's real), Austria has also great history (was a major country until WWI), while switzerland is very scenic and relaxing.
Depending no the time you have, you can really enjoy a hell of a trip.

 

and don't forget to drive the Stelviopass between Italy and Switzerland.
Great experience, especially the first time.