Initially planning to rent a car in Passau (4 persons) drive to Prague returning it to Munich airport a week later. ( no 1 way drop fee). Have a very reasonable rate for one week. However will have to pay car park charges while in Prague.
Was unable to find any nonstop trains, train travel time was hours and train price for four people was expensive. Return trip Prague to Munich also no nonstops, over 6 hours and again fairly expensive for 4 persons.
Thinking about an overnight trip up to Bohemian Switzerland national park. Also considered Cesky Krumlov. Also considering a stop in.Dachau on the way back to Munich.
Any feedback?
The car approach sounds good. Puts you in control and gives flexibility. You need a sticker to drive in Czech but just buy it at the border, it's only about $15. Just pay for the parking in Prague, or also there are lodging options slightly outside the core where you can park for free and take take a quick tram into town. Enjoy your trip!
If you like hiking Bohemian Switzerland N.P. is worth it although it's a little detour on the way from Prague to Munich. Cesky Krumlov is almost on your way. When I come to Prague with a car I usually stay in pension Hattrick where I can park my car in the courtyard. From there there is a short ride by bus to the metro (subway) station. http://www.pensionhattrick.cz . I am sure there are other good places for people with a car, too.
I am presuming you are coming off a river cruise.This company does transfers from the boat to Prague and might be worth considering.
http://www.praguetransport.com/Passau%20to%20Prague%20-%20Prague%20to%20Passau%20transfers.htm
A car in Prague is useless and as you realise expensive to park, so might be worthwhile considering the transfer .