Don't miss out on the Gorge du Verdun, if you hit it at the right time of day, coming up from Monaco, around 5-6ish, when most are off the roads for tea, it's a belter. You might recognise it from when Top Gear test drove the Audi RS4 and raced the two free climbers up a cliff face. We've stayed there on Lac sur Mer, close to Moustiere St Marie (beautiful village)
The Italian Lakes are gorgeous, and offer a not to far drive to Stelvio, also take in Livorgno (tax free haven).
On the Stelvio, watch out for bikers, they don't seem to give a f%*k about cars, from the Italian side it's a pretty hairy drive up!
Good luck, hope all goes well