Non-Touristy Tuscany Among Ordinary Italians
Certaldo area is a great base as it is right in the middle of an area exactly half way between Florence and Siena in which there are some lovely places to see like Certaldo Alto, San Gimignano, Colle di Val d'Elsa, Volterra and Monteriggioni, but it is a regular little town where you will experience ordinary Italian life.
The train line between Florence and Siena, with Certaldo being about half way down it, has numerous stops in ordinary non-touristy towns where they have markets on different days of the week. It is a great area to experience ordinary, daily Italian culture away from the kitch and expense of some of the touristy areas, but with the advantage of ALSO being accessible to famous towns if you want to see them too.
The train station in Certaldo has a free large parking lot behind it so you can easily go to Florence (to the north) and Siena to the south) by train without having to worry about parking.
There are loads of good, inexpensive places to eat local food and there are also many family-run wine producers in this area.
Please check out travi-risonanti.com. There is a winery only a couple of minutes walk away. and they will give you a free tour and wine-tasting.