I'm looking for advice on what to do for a few days in midsummer with an adventurous boy with an interest in history and nature. We would be traveling by train or local buses. He would probably like tramping around the Fussen castles or perhaps Linderhof, maybe a day wandering Liechtenstein, or Berchtesgaden/Zugspitze but those are probably extremely busy then.

Is there a local equivalent of Rothenburg ob der Tauber? Feldkirch?

Is Lindau worth a visit?

The areas around Krimml and Hallstatt look very interesting - perhaps concentrating there and maybe a one or two of the more touristed areas?