Ciao Mitch!
Like glassbloweruk said, the bigger towns are easy to reach by train -
Florence, Pisa, Lucca and Siena (which is actually better to reach by bus since train requires a change).
The smaller towns are also generally reachable by bus or train but require a bit more planning, eating up some of your time - -that is why a car generally comes in visiting many of the small towns in Tuscany (a car is not needed for Florence at all) as well as vaster areas like
Chianti or
Val d'Orcia (both are whole regions).
3-4 days in Rome and Venice sound good, I'd likely do 4 days in Rome and 3 in Venice and that way you have 7 days to divide up between Florence and the rest of Tuscany. You could use Florence as your base for 3 nights, and then also stay elsewhere in Tuscany (would suggest
Siena) or stay the whole week in Tuscany, rent a car and on some days come into Florence to see it (at least 2 days).
What month are you coming? Because a whole week in Tuscany would be great in the countryside at a villa or farmhouse that has been divided into apartments - they generally have apartments for 2 people and larger groups, each with their own kitchen, bathroom, independent entrance and garden area, and a pool to share with the other guests. For accommodation, take a look at this site dedicated to
accommodation in Tuscany - you'll find all types of lodgings.
Ok these are just some first ideas which hope will help you in your planning, feel free to post any other questions that come up as you move ahead with the planning!
