Train
The earlier you book your train tickets the lower the price. I typically book 45-60 days in advance. Give yourself at least 30 minutes before your train leaves.
Rental Car
It is nearly impossible to travel on public transportation above Venice. I recommend getting a rental car to get to the Dolomites. Turn off your toll feature on Google Maps to avoid very expensive tolls. Travel time is slightly more and a lot of roundabouts.
House Or Rental
Outside of major cities can be difficult to find accommodations with hotels.