Trains

Katie, Go to trenitalia.com raileurope.com or dbbahn.com. You can find out the schedule for all trains and cost. In Italy, I think the point to point tickets will cost you less. No reservation needed.
Have good trip.

First, skip Rail Europe as an info source. It is basically a travel agency that sell ticket for a limited number of European trains with a substantial service fee. Second, db Bahn, the Germany rail site, is great if you need schedule info anywhere in Europe but only sells tickets for trains that begin or end in Germany. Trenitilia is the site you want to use for Italy. The site is fairly easy to use but you need italian spelling of the cities. fpr example - Florence is Firenze. If you purchase around ninety to 120 days out you can get some terrific discounted tickets but there is no change or refund of these tickets. Using discounted tickets would be far cheaper than a rail pass. Finally, all train in Italy require a reservation EXCEPT for the Regional trains. The R trains are like a bus on rails - makes every stop, and slowest but cheapest way to go.

Train passes almost never make sense for travel within Italy. Also check out italotreno.it for a competitor railway to Trenitalia. But don't go back to RailEurope.

Instead of getting out really early, I like to take evening trains when possible, after a full day's sightseeing, and possibly have a picnic dinner on the train. Early trains can be crowded with commuters. Unless you have specific things you want to see in Milan, I'd go straight to Venice. Or to Verona, which is a lovely town between them with lots to see. In Florence I recommend the Archi Rossi Hostel (I've stayed there 3 times). They have nice rooms with private bath ("en suite") in the annex and good (free) walking tours in the mornings. It's well located and, maybe more important, they have coin-op washers and dryers (with detergent provided) right in the middle of your 2-week trip. It's also a good opportunity to meet and mix with others (all ages, though mostly in their 20's). You can book directly on their website.

How about swapping Milan with Varenna (or Bellagio) on Lake Como? It's about a 40 min train ride north of Milan. Relax your jet lag away and enjoy the pictureesue lake and small lake towns. You can a all day ferry pass to explore the towns. I am doing a trip similar to yours. We are flying into Milan and going to explore Milan for a couple hours before taking the afternoon train to Varenna for 2 nights. And then onto Venice. I prefer early Am trains to someone who posted evening trains. I'm a earlier riser and would prefer to eat dinner and enjoy the evening in my destination city then be on the train. I'm taking a 7:37 train from Varenna to Milan, and then I believe it's a 9:05 high speed train from Milan to Venice.

I like Robert's idea of reducing time in Milan in favor of time in Varenna-Esino. You would not regret this move. Varenna is a 1-hour train ride from Milano Centrale. For your trip from Milano Centrale to Venezia Santa Lucia, the train ride is 2.5hrs on the very high-speed Frecci train. The high-speed train journey to Firenze Santa Maria Novella is 2hrs. Train rides to and from Pisa and Siena from Florence are just over an hour. Trenitalia charges a 10Euro supplemental fee on top of your Eurail pass for each Frecci fast train that you will be on. I see 4-6 depending on how you travel. You don't need a pass. Your train rides to and from Florence to Pisa and Siena will be on Regionale trains. This are the basic trains that stop at every station. A pass would cover the basic fare but the basic fares are about 16Euro round trip for each. Why would you pay a lot of money for a pass when the fares are this cheap. Secondly, once past Napoli Centrale on your way to Sorrento and the Amalfi Coast, no train, bus or ferry service will accept your Eurail pass. I suggest that you might do a bit more homework on the train websites. If you can nail down some exact travel dates and times, you can buy nicely discounted train fares on the high-speed Frecci trains. For example, my wife and daughter have 19Euro tickets on the train run from Venice to Florence this September. Regular fare is 45Euro.

Just to let you know that you can book trains at the station using the automated kiosks. They have an english menu available, and are no harder to use than an ATM. They might or might not take US credit cards, I use euros. You can book as you travel or buy as many trips in advance as you want. There is a discount for advance purchase, at least a day ahead. Bigger discount the more in advance. As for reservations, the machine automatically makes them when it issues the ticket. Don't forget to validate (stamp) the tickets before boarding. Some tickets require validation, some don't, I play it safe and validate them all. You can find much more train info online. A good starting point is http://www.seat61.com/index.html