I dunno about Prague as I have never been but yes, 3-4 days in Berlin-Munich...depends-personally I was ready to leave after a day but y'never know how you might like it.
If I was to suggest day trips I would say Leipzig for Berlin and Nuremberg for Munich.
I have been to: Canada, USA, Iceland, Britain, France, the Netherlands, Belgium, Spain, Poland, Germany, Sardinia, Switzerland, China, Argentina, Brazil, Chile, Uruguay and Morocco.
Do to list: [color=blue][color=black] Australia, New Zealand, Austria India and Bolivia.
[color=blue][i][font=Verdana][color=black]"I'm just another stranger lookin' for the promised land"