Car travel from Avignon to Florence.

Unless they've moved one city or the other, your distance is off -- it's something less than 450 miles. If you keep up with traffic and don't dwaddle in the slow lane, figure less than six hours to the fringe of Florence.

ViaMichilin is inaccurate for freeway times on the continent.

Driving time is a variable, but I expect the distance given at viamichelin.com is accurate. It's 699 km which equals 434 miles.

Be aware that picking up a rental car in one country (France) and dropping it off in another (Italy) will result in a hefty international drop off fee. If you're going to spend that kind of money, then take advantage of the flexibility a car affords you. Stop and take a walk when you're in a scenic area. Spend the night somewhere enroute.

Get off the motorway from time to time and explore a bit. On Michelin maps stretches of road that are especially scenic are highlighted in green. For example, when you get to Frejus/St-Raphael you could take the DN 7 and the D 6007 to Mandelieu-la-Napoule and rejoin the motorway there.

What Tim said!
The roads are good.
Unless you are really on a tight schedule, the south of France is a delightful place to break a journey.

Thank you for the suggestions!

You can also fly to Florence (or Milan, or Rome, etc) on Brussels Air Line, but you have to leave from Marseille, 65 kilometers SO of Aviginon.

You can also fly from Marseilles to Rome or Milan on German Wings air.

These are all lo-cost inter EU airlines.

Carrie,

If you don't want to stop and explore along the way,
take the train to Nice,switch to the slow train and get off in San Remo, this will save you at least $300.00

We did this 2 years ago and it worked out very well.

You can then cut across the mountains toward Parma/Bologna and then to Florence.

The roads are much like our interstate system.

Check out Kemwell for car rental.