I've just booked a flight to Brno in December and from there plan to go to to Cesky Krumlov. I've got a few days to spare after that and am not sure where to go. Salzburg, Linz or Vienna are possibilities - can anyone suggest anywhere else? Are there any hidden gems in that region?
For surely you should visit Passau in Germany. Moreover I would recommend to you to buy Bayern ticket (deutsche bahn) and first to visit Salzburg (everything is situated in the city center, a couple of hours will be enough) than with the same ticket you can visit Passau and than back to Brno. If you have more time you should visit Vienna as well :-)
Thank you! I'm definitely going to Salzburg and will consider Passau too.