Has anyone done a day trip by train from Budapest to Vienna? I know the train takes about 2 1/2 hours. I was then thinking about doing hop on off bus in Vienna. Any suggestions ...?...or is this too much for one day?
Vienna is definitely too much for 1 day. you probably can do the bus tour but you're not doing its justice.
When I was in Vienna in 2010, they had just revived the HOHO tram. There was no HOHO bus. I agree that Vienna deserves more than one rather short day. What about flying open jaw and spending 2-3 days there?