Hello fellow austrians!

I have an upcoming 6 day trip starting from May 27th and I want to choose a town somewhere on this train line, preferably in the middle because the train trip is quite far away from my hometown (Hungary).

Is there any town that’s worth a short 1 night visit?

Context: I would be a first time solo traveller and I will only stay for 1 night, since I had some huge arguments with my parents about my original 9-11 day trip (they think the outside world is too dangerous for solo travelling), so I have to seriously compromise in terms of days that I can spend abroad. (24 M)