My husband and I will be in Vienna for 3 days in mid-July. No car. Is there an interesting day trip we could trip using the bus or train? I'd like to see the countryside. Thanks!
That would be my recommendation also, as it's one of the most spectacular sites in Europe IMO. Another interesting option to the east might be a quick train or boat trip to Bratislava. If you only have time for one daytrip, however, make it the abbey.
MELK!! The abbey is outstanding.
We joined a biking/winery tour that took us around the Danube. Great day. Unf it didn't allow any time to go to the Melk Abbey but I think it was worth it.