train or rental car from Vienna via Hallstatt to Salzburg?
Single or with others? For 2-5 people, Austrian Rail has an all day pass for regional trains for €28. (Try to rent a car for €28 a day, with fuel). But, one person can't use it, even if he pays the full €28 himself. That's why I decided against my all-Austrian trip in 2009.
The train works very conveniently for this trip.