Speaking of Austria, I'd recommend the Japan Alps!
Since you're in Tokyo, take a train to Matsumoto (see the castle there, if you haven't been to a castle yet. It's a nice one), then take a bus to Kamikochi, in the Japan Alps, hike there all day, and take a bus to Takayama at the end of the day (or spend a few days in Kamikochi if you like). Next day, hike around Takayama and the Hida Folk Village, which is a historic Japanese town. From there, you could keep going to Kanazawa and see the park there, which is beautiful.
It's a very nice trip, I did it myself, in reverse since I was starting in Kansai.