Travelling by public transport to San Quirico
Buongiorno,
Here are some suggestions, but you will need to double-check the availability and TIMES (depending on the day you travel) as you get closer to June. Train schedules normally change in June once school has let out - so though you can make general plans on how to move around, you probably shouldn't be checking times till a bit later in your planning stage.
There is a train from Orvieto to Chiusi - and from there it appears you can catch a bus to Montepulciano and another bus to San Quirico. I am totally surprised that all of this only takes about 2 and a half hours.
Getting to Venice takes a bit more time, essentially you need to get to Florence where you can catch the train to Venice. From San Quirico, you will catch a bus to Buonconvento, which will give you access to a train to Siena. From Siena, you can easily get to Florence to catch the train.
It will probably be easy for your accommodations to assist you with making the arrangements to Florence because it is all in the same region and busing options are a bit more organized.
Buon Viaggio,
Donna Denise