What would be the timeliest way for two people to travel between Vienna to Venice during Carnival season (mid-February)? I would like to maximize my time enjoying Venice over two days rather than spending most of that in travel, but still maintain something of a budget. I've considered sleeper trains, renting a car (pick up and drop off in Vienna), and possibly flying for both of us. Tickets are not listed on any rail website yet for February, so I can only guess what they might be. Advice is much welcomed!
On the Austrian Rail site you can book tickets up to 120 days in advance for either the direct Vienna-Venice night train or daytime routes that require at least one connection. Doing so can get you a very cheap discount fare.
To get an idea of the prices and routes, just look at dates no more than 120 days out - you'll see the range of prices from full-fare to best discount. And FWIW, I like to purchase tickets from the 'home country' when possible. If there's a problem with making the train in Vienna, you're not trying to exchange or make changes to a ticket issued by an Italian company...