...a couple of quick observations if you will be visiting Florence in the near future:
1.) I think the Firenze Card (museum card) is well worth the 72 euro. It gives you 72 hours of access to almost all of the museums (one time at each site). Florence is very walkable for most, but the card also doubles as a 72 hour bus pass as well. The big benefit is that it allows you to enter museums in the "reserved" line which can save you a lot of time. The lines at the Accademia and Uffizi were, as expected, very long. I was able to get into each of those sites in less than 10 minutes.
2.) The mistake I made was waiting in line at the Palazzo Vecchio to buy the pass. That took a while. You can buy the pass at many locations. One of the best sites was the Basilica Santa Maria Novella (right across the street from the train station). Not only was this a great site, there was no line to get and they sell the Firenze Card there. My recommendation is to make this an early stop, enjoy the site and buy the Firenze Card there.
3.) The Baptistry next the Duomo is covered with scaffolding on the outside but is open for business on the inside. The famous bronze doors are mostly visible on the outside but not entirely. The Duomo museum is supposed to be open for business within the next couple of weeks. Unfortunately it was closed when I was there.
4.) Day trips to Siena and Lucca are easy. 1.5 hours each way by train. Round trip tickets are 16 euro. Make sure you validate your train ticket (using a green machine that stamps your ticket) before boarding.
Happy travels!