CarSwami

I also give a thumbs up to Salzburg and I too feel that 3 days in Zurich is more than you need to spend there. My suggestion would be to spend some time in Luzern if you have not visited it. I would also recommend spending a day or two in the Berner Oberland area. You could use Interlaken as a base camp to visit this region but my preference would be to use Murren as the base camp. However, I should point out that the Berner Oberland area is best seen using trains and cable cars, it is not really set up for driving and cars are not even permitted in some small towns like Murren.

neuroaudi

Meersburg is one of the most beautiful small towns I have ever been (spent one night there), and quite a surprise, although some of the towns around Lake Constance are more dry and snobbish in my opinion. Neuschwanstein Castle is always a top choice for a Newbie (did it on my first of three ED trips), maybe with what I know now about other more interesting destinations I would skip it. I think you could do a lot better and have a more linear (or circular) experience than deviating south to Innsbruck or spending 3-4 days in Zurich. You could drop off in Munich or Paris instead, for the former there are plenty of small and very interesting Bavarian towns you can explore that are more amenable to driving, for the latter you can stop in Alsace, Meersburg, Heidelberg, even Beaune on your way to Paris. Choices are endless and it really depends on your interests, but most people take the advantage of the car to hit the more intimate and off the beaten path small towns rather than the top 10 google city destinations. I would personally avoid Salzburg, indeed a great city but again with all the options if you really do your homework you can see some serious culture and not have to deal with driving, parking in a bigger city. Just my 2 cents. Good luck.

chicagoA6

We stayed last year in Landau / Lake Constance and I would agree that the Lake Constance area has some lovely towns. Spent two nights in Landau before heading to Salzburg.