Cajun,
When I posted a reply last night, I didn't realize that you'd be travelling to other countries other than Italy, especially over such a wide area. I definitely agree with Kathy and the others that you need to take a close look at your plans, as travel by car for the entire trip is not the best idea.
In addition to the very expensive surcharges for renting a car in one country and dropping in another, you'll have to be aware of highway tax vignettes in Switzerland and other countries (hefty fines usually collected on the spot!), highway speed cameras (including the Tutor system in Italy which measures both instantaneous speed as well as average between two points), Tolls and high fuel prices. An International Driver's Permit is also necessary in France.
If this is your first trip to Europe, I would highly recommend reading Europe Through The Back Door prior to your trip. For more detailed planning for transportation, hotels, etc., use the Rick Steves guidebooks specific to the areas you'll be visiting. Your local Library or larger bookstores should have these. Using trains (especially high speed versions) will be a much better use of your holiday time as they'll get you from point-to-point much faster. The high speed trains operate at up to 300 km/h, which no car can match. There are a few potentially expensive caveats to be aware of when using public transit as well. Post another note if you need more details on those.
If you'd like to share more details of your proposed Itinerary, I'm sure the group here could offer lots of suggestions.