What to do when travelling alone in Europe?

I’ve planned a trip to Europe this year for late May to early August. My parents will be accompanying me for part of the trip, and leaving me in Vienna where I plan to do a German language course. The problem is, I’ve left it a bit late to book a return flight plus I want to use Frequent Flyer points, leaving me with few flight options.

I have 1–2 weeks between the end of the course and the next available flight, which will probably be from Frankfurt, Vienna, Prague, etc. Obviously, as a solitary young female without a firm grasp of any languages other than English, I’m looking for something structured to do in this time, rather than hanging around youth hostels chatting to strangers.

I’ve looked at a variety of Contiki-type tours and there aren’t any that perfectly fit my schedule/budget/comfort level/places I want to visit, so I was wondering if anybody knows of any boarding houses, homestay programs, etc. that would be interesting for me and reassuring for my parents? Or are there any other options for a short time alone in central Europe?