hi.

As you travel through several countries you will need a GlobalPass :)

Depedning on your shedule and personal interest.
You have to decide if you want a consecutive pass (Valid on every day of a specific period like 7days, 22days up to 3months are sold) or if you wanna buy a Flexipass (valid on specific days you select for example 7days in a month or 15days in 2months)

Kind regards
@seewulf 

IF you really only plan to make these trips, then I doubt if a pass is worth its money. Check-but then you are tied into those bookings- what advance tickets would cost and use RegioJet for od Praha do Vien. NS-INT has a promotion for 30€ for NL-Berl. But likely you are junior so get lower priced pass. How come back? Fly?  And till 31/3 there is 10% discount too.

AND good-you have found a route that does not need mandatory REServations-though some in high peak season might be worthwhile.