Alas, we ended up taking the fast route from Grenoble to Bolzano, though my gosh, I'd forgotten how high the tolls can be in Europe. I think we ended up with something approaching 120 Euros, with the big one being the 35 Euro tunnel fee. Mr. Daregale took a different route back to stop and hike at Col du Lautaret and thus avoid the tunnel on the return.
The trip in general left me itching to return. Grenoble was truly lovely and kid-friendly. Lots of spiffy playgrounds and splashful water fountains, dirt cheap bike rental (child-seat included!), sweet toy stores and window shopping. And I don't know quite what I imagined with Bolzano--something much smaller, I guess. But so many easy and lovely hikes for a three-year-old and almost-80-year-old. The romance of the mountain farm, hearty and fresh local food, tempting wines--I'm looking forward to a longer stay next time.