and then you can cherry pick a couple places in southern Germany (Neuschwanstein), Slovenia (Lake Bled and Postjona Cave Park). I'd spend 10 days around Interlaken in Grindelwald or Lauterbrunnen and 2 weeks in Italy (Rome, Lake Como, Cinque Terre, Pisa, etc.) There are many incredible places to visit in Europe, but this is an excellent corridor to spend a month in.