What is the best scenic driving route from Bellagio to Ortisei in Dolomites,

Whichever route you decide to take, you will have a long drive. The viamichelin.com website suggests two routes. The first and fastest is 4 1/2 hr going south from Bellagio to Bergamo and east to the Brenner Pass north(mostly autostrada). The other "fast route" is 6 1/2 hr north out of Bellagio to Sondria and east thru the mountains to Bolzano. The recommended "scenic" route is 6+ hr and goes south to Bergamo and east to the western side of Lake Garda and north to Bolzano. I'm assuming you have maps etc.

I know you want to take advantage of the scenery but you will be going to spectacular scenery and one of our great pleasures is to admire the scenery of the Brenner Pass--and it gets you there easier and faster. I suggest that route--enjoy Ortisei (St. Ullrich). Hope you have good weather.

I have taken 2 of those routes over the years and it really depends on your time and the weather. And, Ortisei is really south of the Brenner Pass, so that is not a factor. I would get there ASAP via the Autostrada and then take the Bolzano Nord exit that will take you to Ortisei via Castelrotto---a pretty drive for the last hour of the route.

The best scenic route would be taking a ferry to Varenna, then driving Colico - Sondrio - Bormio - Stelvio pass - Merano - Bolzano - Ortisei. The Stelvio pass is closed for snow most of the year and has 84 hairpin turns (36 ascending and 48 descending). So it is an extremely tiring drive and not to be tried unless in optimal weather. Still, it is the shortest and more scenic itinerary.

My advice is driving to Bergamo and then the Brenner highway. But now you know the alternative.