Yes, there is a direct bus departing from Vienna Erdberg and arriving at Berlin central bus station station. Services depart every three hours, and operate every day. The journey takes approximately 9h 25m.
Is there a direct train from Vienna to Prague? Yes, it is possible to travel from Vienna to Prague without having to change trains. There are 12 direct trains from Vienna to Prague each day. Though there may be fewer direct services available depending on your exact departure date.
That leaves 7.5 days (4/23-29, and part of the 30th) before you leave Prague. Consider you'll use up time getting between cities. Train travel time (on non-stop trains) for Prague - Vienna is 4.5 hours; Vienna-Budapest 3 hours; Budapest-Prague 7 hours. Don't know if the pass lets you take non-stop trains, so you may have much longer travel times.
Direct Vienna – Prague Trains. Some routes are served by both direct trains and trains with connections. Similarly, different train companies may provide all or part of a journey with different offers. To find the cheapest tickets, you can check the best prices by searching SNCF Connect.
EjpChl9.