I am also looking into an Interrail pass, for example for 5 or 7 days within 1 month.
Question: if you start with the direct night train from Arnhem to Vienna (which then departs on Tuesday evening for example and arrives on Wednesday morning), does that count as 2 travel days or 1 travel day?
And does it make a difference if you book a non-direct night train?
Are there terms and conditions where I can find that?