Starting in Siena for surprise birthday

If you start in Sienna, just take your time to breathe and stay in Siena for at least 3 nights. ( you Will need two full days) Take day trip to Cortona, San Gimignano, and if you have children to Collodi, Pinocchio's village.
Take 5 ( 4 full days)nights to get a feel of Florence
Take 6-7 (5-6 full days) nights to get a feel of Rome, Rome is huge!
Take 4-5 nights ( 3-4 full days) to get a feel of Venice.
Easy train connections from either Rome or Florence to Venice.

Andrea,

I assume that you're not planning to spend the entire two weeks in Siena? There are LOTS of possibilities, but it would help to have some idea where your inbound and outbound flights are from.

As this is your first trip to Italy, you'll need to be aware that there are some potentially expensive "caveats" with regard to both trains and other public transit, as well as rental cars. Here's a brief summary.....

• Tickets for Regionale trains, Buses, Metro, etc. MUST be validated prior to boarding on the day of travel, or you'll risk hefty fines which will be collected on the spot!
• Tickets for the high speed trains have compulsory seat reservations, which are specific to train, date and departure time, and can ONLY be used on the one train listed on the ticket. If you board the wrong train by mistake, you'll be deemed to be travelling without valid reservations and again, hefty fines on the spot!
• When using rental cars, drivers must have the compulsory International Driver's Permit, which is used in conjunction with your home D.L. Although I've never heard of this happening, failure to produce an IDP if requested can also result in hefty fines collected on the spot!
• When driving in Italy, you'll need to be extremely vigilant to avoid the dreaded ZTL (limited traffic) areas which exist in many Italian towns and cities. EACH pass through a ZTL area will result in, you guessed it, hefty fines. In this case, if you pass through automated cameras you won't know you've been nicked until several months after you return home. Florence is just about saturated with automated ZTL cameras.
• You'll also have to be vigilant to watch your speed, due to automated photo radar cameras. There is little-to-no leeway given for those who exceed the speed limit. The motorways also use the Traffic Tutor system which measures both instantaneous speed as well as an average between two points. If you exceed one or both, hefty fines will follow.
• You'll have to budget for tolls on the motorways and high fuel costs.
• A GPS or at least a good Map would be prudent.

I find that using public transit is the easiest method, as once you learn the "rules" it's not difficult to avoid fines. Trains are also much faster and a better use of valuable holiday time, especially the high speed versions which travel at up to 300 km/h.

Thank you Ken for all suggestions. If I land in Rome and start my vacation maybe we could just use the trains? How do I plan the trains ahead of time ?

Andrea,

Yes, you can absolutely use the trains. That's often the quickest and most efficient method to get around.

To check rail schedules, you can use either the Trenitalia or Bahn.de websites. Some tickets can be purchased in advance at a considerable savings, and you can buy those either from the Trenitalia website or www.captaintrain.com (which sells tickets at the same price as the rail networks and has a very user friendly website). On some of the rail routes, you can also use Italo Treno which is a competing high speed rail network.

As I mentioned in my previous reply, there are a few things to be aware of when using trains and other public transit, but it's very easy to get used to the rules.

Siena - 2 or 3 nights
Cinque Terre - 2 nights
Milan - 1 night
Venice - 3 nights
Florence - 2 or 3 nights
Rome - 3 nights

Are your dates firm? You could possibly start in Venice, go to Siena for the birthday, and end in Rome to fly home. You will not need a car unless you want to see more of the Tuscan countryside. You can get to Florence by bus.