Novice Traveler

Many experienced travelers to Italy will tell you, as a rule of thumb: if trains go there, take the train.

However, one of the exceptions to that rule of thumb is: if you wish to efficiently see the Tuscany countryside, a rental car provides more flexibility. But don't drive your rental car in Florence; and in general, it's a needless hassle to have a rental car in the larger Italian cities.

You can fly into Venice; or you can investigate whether flying into Milan and taking the train to Venice would save money. However, if you did it that way, you would be back-tracking (somewhat) to get to Tuscany from Venice.

If you know you want to go to Venice, flying into there is probably the best idea.

You can guage whether you would save enough flying into Milan to change your itinerary - it's a long ride from Milan to Venice, so keep that in mind.

As for one other city, Florence is the obvious choice because it's in the right direction and has a lot to see. We loved Verona. You could also try Balogna or Assisi.

We drove a leased car which worked well in some places and not as well in others (Venice and Florence were two places it didn't work well). If you drive, don't leave home without a good GPS.

I wouldn't go to Switzerland in the time you have, there is plenty to see and do in Italy without adding the time and expense of detouring to Switzerland.

it's a long ride from Milan to Venice, so keep that in mind.

Milan to Venice is only a 2.5 hour journey by train (direct).

I would fly into Milan or Venice... And by all means... take the train if it goes to where you are wanting to go. I think a car more often hinders travelers than helps. Some of my favorite Italy experiences are not places but watching families with their kids, young teens etc on the trains. Neat stuff.