Wife and I am traveling from Rotterdam to Munich in June. We would like to go by train (this is our preference over a flight). Best itinerary has us going on an NS train from Rotterdam to Utrecht. Then, in Utrecht, we switch to a German ICE train to Frankfort. Then, transfer to another ICE train for last leg to Munich. I have a couple of questions.
1) Is there an advantage for buying tickets from DB instead of NS? They both offer the same itinerary at the same price.
2) From what I have read, it sounds like I should be able to catch any NS train to Utrecht, regardless of time. However, I am "tied" to the two ICE trains a the times stated. Is that correct?
3) Do I need to validate (swipe in) before getting on train in Rotterdam?
4) When I transfer from NS to DB in Utrecht, do I need to validate the ticket in any way (swipe in or out)?