My husband and I have 4 days in Florence and we would like to take a day trip to Siena & San Gimignano. It doesn't look like this would be easy to do independantly via train/bus. But, we're not fans of organized tours either. I've been looking for just a transportation package that includes transfer between the two cities, but have yet to find such a thing. Does anyone have any other suggestions? Many thanks!

It's very easy to bus to Siena (or San G.). The bus to Siena takes about an hour and the bus drops you at the edge of the historic center (train does not). You want the rapid bus (on left side of schedule) for Siena. It's about 6€ one way.
http://www.sitabus.it/sita-toscana/Firenze-Siena06.pdf

San G schedule is on page 2 of above link.

Thanks for the link, Kybourbon. I think I had checked out the Sita site before, but we're wanting to do both places on the same day, and I didn't see a route that went from Siena to San Gimi?

You could take an early bus to San G. and then catch bus 130R on to Siena. Be sure not to miss the last Sita bus back to Florence (last Siena/Florence train is about the same time). Here's a map of buses from Siena.
http://www.sienamobilita.it/mappe/Mappa_EXT.pdf

Here's the schedules (may take a minute to load). You will have to scroll through to bus 130A and 130R. Pay attention to the legend symbols (ask if you don't understand one) and that the bus starts and stops at your desired points.
http://www.trainspa.it/train04/extraurbano.pdf

Hulz,
This may help http://www.sitabus.it/sita-toscana/f...ignano2010.pdf

We did it the easy way by booking a private tour guide at hillsandroads.com. His name is Luca.

Thanks for all of the links! Looks like I have some reading and route planning to do tonight!