Germany, Austria, Italy?

Yes, you have enough time. Why don't you see if you can book your flight going into Munich and returning form Venice? Or vice versa, then you don't have to backtrack.From Salzburg to Venice, there's a night train you can catch in Innsbruck at 23:04, arrives in Venice at 7:37. You take a connecting train from Salzburg at 21:00 that arrives in Innsbruck at 22:59.

This night train originates at Munich, departing there at 21:03 and getting to Venice at 7:37.

I would actually throw in another city, but I can cover a lot of turf in a short time. Most people will tell you the opposite.

Train schedules: http://www.oebb.at/en

Yes, you can do this. Salzburg is only 1.5 to 2 hr by train from Munich depending on the specific train. You could do this as a day trip from Munich if you wanted. There are night trains between Munich and Venice that are good options. You can get a berth on the train, sleep through the night and arrive at your destination in the morning.

There are only a couple of direct trains between Venice and Salzburg, but there are several options with only one change. The night train from Salzburg to Venice is a little less convenient - it leaves at 1:38 am and arrives in Venice at 8:45 am. Going the other direction, there's a night train from Venice at 8:28 pm that arrives in Salzburg at 4:05 am. there's also a night train that leaves Venice at 8:51 pm and arrives in Kufstein at 5:25 am. There's a train from Kufstein to Salzburg at 5:44 am which arrives in Salzburg at 6:57 am

Train schedules and prices: http://reiseauskunft.bahn.de/bin/query.exe/en

http://www.ferroviedellostato.it/ferrovie/util/ing...

http://www.oebb.at/en/index.jsp