I need to get to Sinalunga on a Saturday by bus or train. I will be traveling from Siena. Please advise. Thanks.
Easy to do by train. Journey takes less than an hour on a Regionale train. Fare is 5.20Euro. Note that you can't reserve Regionale trains in advance. You buy your ticket, validate it in the little yellow box in the station, get on and find your own seat. It's like a bus. Here's a LINK to a typical saturday morning schedule. Note the very few trains during the morning hours.
Jean,
Check route 107 http://www.trainspa.it/en/home.html