Driving from Bolzano to Venice

Honestly, I would not be too scared of the mountain roads. They are beautiful and worth any effort. We just got back from two weeks in Italy and rented a car for three days in the Dolomites. They were my favorite part of the trip.
If I had 7 hours to get from Bolzano to Venice, I would drive straight through the Dolomites to Cortina d'Ampezzo. This may be one of the most scenic drives I have ever done. You need to go over a couple passes along the way, but Italy roads are so well maintained. It is curvy, so the route is slow, but breathtaking! Go along SS 242 through the Val Gardena and Alta Badia valleys and on to Cortina D'Ampezzo. Google maps shows this as a 2 1/2 drive. You will want to stop and eat and take a million pictures, so count on 4 1/2 or so. From Cortina down to Venice is about 2 hours, but you would not need any stopping along there.

We left the area driving along the eastern side of Lake Garda and stopped for a brief lunch in Sirmione. It is pretty at the lake, but nothing like the mountains.

Have fun!

Thanks for your advice Becky! I was actually thinking of doing the mountains so will give it a go!

(without scary mountain roads without guardrails)

There are guardrails.

East side of lake down through Malcesine has very pretty mountain views. We drove both sides of the lake going to and from the Dolomites, not scary driving at all.