I know I sound like somebody trying to do too much, I had sceduled two full days (three nights in Prague) and I didn't think of visiting Cesky Krumlov when planning dates/how long to stay in each place. My question, is it worthwhile to visit Cesky Krumlov on one day and spend one a half days exploring Prague? Any help/advice will be appreciated.
You'd really be shortchanging yourself if you gave only 1 1/2 days to Prague. It's one of Europe's greatest cities.
Cesky Krumlov is great, but I don't think it's worth doing unless you can spend 1-2 nights there. Save it for another trip.
No.
I agree that a day visit to Cesky Krumlov from Prague is not really feasible and you should certainly spend more than one full day exploring Prague. If you have the opportunity to get to Cesky Krumlov for two or three days it is well worth it.