Key point from Austria is Insbruck. In Italy highway continues to Bolzano. This way is fast to many groups, e.g. Catinaccio, Puez, Brenta, Marmolada, Latemar or Pala. In Italy road continue to Dobbiaco. Or turn to road nr.
Night is better time to drive, there are less cars on highway.
But navigation at night is more difficult. I very like early morning after long driving in Italy. It's nice for my heart, if I may look at sunrise from some mountain. If you have luck, then sky change from deep dark to glittering blue, mist boiled in valleys, tinkling dew and snowed Alps at horizont. Basic info's about easy climbing at Dolomites are available in OK1DUO selection .