I've found the trenitalia site quite easy to use, but attempting to figure out bus timetable has thrown me for a loop!
I am trying to determine bus service/times from Chiusi to Montepulciano on Sunday 10th of May, then a bus from Montepulciano back to Chiusi on Wednesday 13th of May.
I tried using the site referenced in Rick Steve's excellent Italy book: http://www.sienamobilita.it/
Their english language option doesn't quite seem to work, throws an error in my browser, but that's fine, because the other site, mentioned www.lfi.it, seems to lead to the same timetables at http://www.tiemmespa.it/
From there I clicked on Orari Servizi then Orari linee LFI in Siena Mobilità Scarl then MONTEPULCIANO - S. ALBINO - CHIANCIANO - CHIUSI which sounds exactly like what I want, which pulls up this PDF http://www.lfi.it/orari_linee_si_mob/F_T4.pdf . Here I'm at a bit of a loss. It seems the A trains run from Montepulciano to Chiusi, and the R buses run from Chiusi to Montepulciano. I assume I want to go from the Chiusi train station - Chiusi Stazione (we will be arriving by train from florence) to the Montepulciano bus station - Montepulciano autostazione. I don't want to end up at the montepulciano train station.
I don't know how to tell if a particular line runs on Sundays. It seems like 906404 would depart Chisusi train station at 11:25 am and arrive at Montepulciano at 12:15 am which would be perfect!, but I have heard many buses do not run on Sundays at all and I can't tell from the tables what days the particular routes are available.
Returning from Montepulciano to Chiusi, it seems there are buses at 6:55 and 8:35?
I assume the 'si effetua final 15/10' means the last time that bus runs is on Oct 15th?