We are traveling with our family of 4 (2 adults and 2 teenage girls) and will only have 2 days and 2 nights in Vienna. Our daughters really want to go to Salzburg and do a 'Sound of Music' tour for one of the days. Our plan right now is to see Vienna the first day, and the second day take the train back and forth to Salzburg (get back at around midnight). Do you think that is too much for two days, or should we just skip Salzburg? Girls are leaving for college in a few years and with so much more of the world to see, we probably won't make it back any time soon.