cesky rumlov as day trip from prague or on way to vienna?

We were there last Sept. and would recommend you do what we did, make it an overnight stop on the way to Vienna. It is not as crowded with tourists as Prague but it is still on the touristy side. About 5 o'clock the day trippers go back to Prague and you can enjoy the town. It is a pretty town and is highly walk-able but vertically oriented. There is plenty to see.

thanks so much for the reply irv, i just started planning and read that it's harder to find transportation from cesky rumlov to vienna. How did you handle the transportation between prague/cesky rumlov and cesky rumlov/vienna?

It is not the kind of transport I'm used to, but there is a shuttle bus service to and from Cesky Krumlov (here is their website).
Not wanting to sound pedantic, but mind the spelling: it is Cesky Krumlov (with a K).

I used CK Shuttle this past fall from CK to Vienna and was pleased with their service. I got unlucky with the middle front seat between the driver and another passenger. That was less comfortable than an airline middle seat, though it might be ok if you're friendly with the other passenger.

Everything else was just terrific and they were right on top of all communications.

My recommendation would be for the overnight because CK is so pleasant in the evening after crowds thin.

Sounds like a great plan to do an overnight in CK. We are going the opposite direction from Budapest>Vienna>CK>Prague. Since we are spending 5-6 days along the way, we are staying 2 nights in CK. Based on recommendations from friends we are taking the CK shared ride Shuttle from Vienna.

thanks so much for the replies everyone! i followed all your advice and am staying the night in Cresky Krumlov (and sorry for misspelling it in the title)