Before the advent of teh interwebz, railing in Europe had a train-based accommodations hack. When trying to visit a number of cities in not many more days, you

Before the advent of teh interwebz, railing in Europe had a train-based accommodations hack. When trying to visit a number of cities in not many more days, you could take an overnight into City X, arriving in the morning, and leave that same night on another overnight to your next city. This had the distinct advantage that you didn't have to waste most of a morning trying to find a room - not in a hostel, not anywhere. You had one day - but the full day - to explore. The disadvantage was that you might have to deal with currency exchange (pre-Euro!) when making those same-evening sleeper reservations. In particular, Copenhagen was a PITA. Cash only, Danish crowns only, ripoff currency exchange only.