Ciao Maxwellcook,
I copied your post over to a new thread to make it easier to find and reply -- as craigmillar suggested.
4 days will fly by, I suggest using train as a means of transport and dividing time between Florence and Lucca, 3 days and 1 day in Lucca. Or just use Florence as your base, since you can visit Lucca and Pisa on a day trip and then return to Florence to head on down to Rome.
You can dedicate two full days to Florence this way, a 3rd day to Siena (with bus) and the 4th day go to Pisa in the morning, Lucca in the afternoon and return to Florence by evening (via train). If you don't want to go up the Leaning Tower in Pisa and want to skip that, you can spend the entire day in Lucca! ;-)