I am doing our itinerary and if possible would like an idea of how long it is from paris to wengen. Is it 6- 8 hours? I would like to time it so that it won't be dark yet when we get to wengen. Thanks.
You can figure this out yourself at the German rail site.
The answer depends on which train you take, between 6 and 7 hours. But you might want to stop in Interlaken to buy supplies.
You can check schedules at the Swiss Rail site:
Depending on which departure you do, the journey takes between 6.5 to 7 hours. Connections are in Basel, Interlaken, and Lauterbrunnen.