Nice to Lyon

Are you sure you want to drive? If you had more time I'd say, great road trip. But this is a lot of driving. And the trains are great, and FAST. Much faster than a car.

Yes, we are driving only because we are taking the car (our friend wants to drive) down to Sardinia, staying there for a while and then looking for a more scenic route back than the freeways. I realize it will be a lot of driving and I would prefer trains, too, but not my call. Yes, it will take four of us to watch out for the radar and cameras. Any suggestions on a route and where to stay?

If you had enough time I would suggest over the mountains following the Napoleon Road through the Alpes de Haute-Provence . My concern is that you don't have enough time to do much more than the Autoroute...

One suggested route could be the following: 1) Nice to Aix-en-Provence 2) Aix-en Provence via Luberon in Provence to A7. Visit Lourmarin and Avignon on the way through. Not sure how much time you have to wander through Provence. 3) A7 to Lyon. 4) If you don't have time, A31 to Beaune and Dijon. If you have time, go east to Annecy and possibly Chamonix-Mt. Blanc.
5) A31 out of Dijon to Nancy and onto to Luxembourg. For the remainder, I'm not familar with Belgium. Also the big hint is to stay of the major toll roads. There are smaller roads that closely parallel the major toll roads that go through the most beautiful villages. But so do the large 18-wheelers. It's really scenic but it will take you more time. And, it will save you a lot of money as there are no tolls. The French toll roads are expensive. On a few longer drives close to 170km, we paid 20E to get through the toll booth.

Thanks to all for your responses. They have been very helpful.

No tolls in Belgium except the tunnel under the river in Antwerpen.