Family of Five transportation options

When choosing a rental car consider a station wagon. Minivans aren't as common in Europe as they are in the US or Canada. They can be very expensive to rent and more difficult to park. Luggage space for 5 might still be tight but doable if you pack carefully.

You're probably going to want to do a combination of both. You're not going to want a car in Paris, Venice, Florence, or Rome, and drop-off rates for renting a car in one country and dropping in another can be quite costly.

If you do decide to rent a car to do some exploring out of the towns, check the size of the car you're taking, especially if you will be taking luggage with you (if you're just using it for day trips, this won't be the case). You can easily find a car to seat 5, but you'll need a bigger car to fit all of your luggage in.

Fletcher, are you flying in/out of the same city (Paris), or are you flying into Paris and out of Rome? If it is the latter, and depending on where else you want to go outside of Paris, you could do Paris (and surrounding) and then take the train to Italy. There are high fees if you drop a rental car off in another country. Once you have toured Venice and Florence, then rent a car for the hilltowns. Maybe rent the car at the Florence airport. Then drop the car off in Orvieto (a small, quaint hilltown in Umbria) which is a 1 hour train ride outside of Rome. Fly out of Rome.

For car rental, check with AutoEurope, EuropeByCar, or Gemut.com. On the AutoEurope website you can see their fleet of cars and the people/luggage capacity. For the hilltowns check into a GPS (AutoEurope sometimes includes it in a rental) and get an International Driver's license at AAA.

Have fun on your trip making lifetime memories with your family!

Here's what I see: "a couple of weeks" looks like at least ten days in Italy, judging by your list of spots.

Get to Venice by train/plane, rent a car as you leave for all the rest of the Italian places, drop it upon arrival when you get to Rome. Keep it in Florence even though you won't use it since: a. picking up and droping off cars eats into sight-seeing time, b. you might be a tad better off with one longer-term rental than two short termers. Assuming only a couple nights in Florence, net time without a car would only be a day anyway -- you shoot the equivalent of a half day with turning in, droping off, getting back and forth to car place, etc.

That leaves four days or so for Paris. You'll have plenty to do without needing a car.