Train, train, train. While it’s nice to have a car to explore a rural area in Italy, having a car is an expensive nightmare in any Italian city. There are dozens of trains each day to choose from between your cities. Advance purchase tickets from trenitalia.com can be cheap. If you don’t want to commit to exact dates and times in advance, just buy your tickets from the automated kiosks in the train station. Unless 3 or 4 of you can cram yourselves and all your gear into a subcompact, train will be cheaper.

It can vary, depending on the size of your group. Compare the cost of a rental car big enough for your group and your luggage, fuel, and parking (the advice to not drive in Italian cities is good), with the cost of train tickets for the entire group.

Some people have a lot of luggage and feel it is inconvenient to load that onto a train; my wife and I travel with three wheeled cases and two shoulder bags, and have been able to get on and off trains. Although, as I age, it is more and more common that a kind stranger will help with our bags.

On the other hand, train stations are almost always in the center of the city (contrast that with airports), so they usually get you very close to where you are going. Also, trains are faster and let you watch the scenery instead of the traffic. And the trains usually have little tables, so you can pack a picnic lunch and enjoy it (rather than buying the more expensive and staler food sold on trains) which is not easy to do in a car.

Since you don’t indicate that you want to be wandering the countryside, I think trains are your best option. If you want to wander in the Tuscan hills, take a bus or train to a village, then rent bicycles.

thank you guys! =D very helpful answers! train it is!!!