We(2) will be touring for 17 days in July using trains for all connections: Vienna-Budapest-Krakow-Prage-C.Krumlov-Vienna. It appears that buying the European East Pass-2nd class-is a good deal. I am unclear on reservations. Only one night train(Budapest-Krakow) and we can reserve before we leave & have a sleeper car for 2. Is that necessary? Also are reservations needed for the other connections? How do we know which ones? Or can we just walk on? Also concerned about getting on the right cars. Any help is appreciated.
The DB timetables will tell you which trains require reservations. If you see a red circle with an "R" in it, that train requires a reservation. Click on the drop-down menu in the upper right-hand corner for English. After you get summary timetables for a particular route, click on "Details for all" to see the connecting points (if any). Any leg that requires a reservation will be marked accordingly.
It's wise to reserve night trains ASAP. They often sell out.
For help in finding the right car, read this article by Rick Steves.