I have booked a Rail Pass for my Europe trip (Aug. 27th-Sept. 14th) and plan on a whirlwind trip (Paris-Gimmelwald-Venice-Rome-Munich-Bacharach-Amsterdam).
1) How likely is it that trains (esp. couchettes) will be booked by the time I arrive in Europe?
2) Can I reserve all the legs of my trip from Paris or do I need to reserve each leg individually from the country of origin? (basically, can I walk into the a Paris train station and reserve a train from Brig to Venice or Venice to Rome or Rome to Munich etc.)