Getting from Zurich to Venice

That's a fairly straightforward trip but will take at least 6.5 hours, or the better part of a day. I'm not sure of the scenery on that route, as I'm usually more concerned with the travel time and number of changes. Note that your departure station will be Zürich Hbf and arrival station Venezia S. Lucia (reservations compulsory).

You can research all the train details using the Bahn.de or Sbb.ch websites.

The easiest and most direct route is to take a train from Zurich to Milan, then connect on to Venice. The scenery between Zurich and Milan is nice with lakes and mountains. There may be other routes that could be more scenic but they are likely to add a significant amount of time to your trip. Since it's already 6h31m, I would probably stick to one transfer in Milan. You could leave at 7:09, 9:09 or 11:09

I think you can hardly go wrong with the scenery on any route crossing Switzerland, so the fastest connections will be just fine and include some mountain views. The scenery from Milan to Venice is more urban and flat.