As others have said, I'd maybe plus up Salzburg by a day - depending on what you're interested in, there are a number of "niche" activities there:
* Sound of Music tour (see a bunch of places that were used in the filming of the movie) (
http://www.panoramatours.com/en/salz...ur-tour-1a-28/)
* Salzburg has a claim on Mozart, so you could take in a concert. (
http://www.salzburg.info/en/art_cult...dinner_konzert)
* The cathedral there is freaking gorgeous (and I've seen a lot of cathedrals).
Alternatively, the Berchtesgaden area is beautiful. Hitler's Eagle's Nest (Kehlsteinhaus -
http://www.kehlsteinhaus.de/en/) is there, as is the Königsee. They offer boat rides to secluded islands (
http://www.seenschifffahrt.de/en/koenigssee/), where there is a tiny little church out in the middle of the lake. There is a flat stone cliff, and your boat captain might bust out a horn and play an alpine tune against the wall so you can hear the echoes. Also easy hiking trails, and just a lot of great Alpine nature. Really able to be alone with your thoughts out there.
If you go there, I highly recommend trying to get a room at the "Höher Goll" gasthaus, or if they're full, at least eat at their restaurant. Fantastic 800-year old beer recipes served in stone mugs, and the food is second to none.