how far in advance do train tickets go on sale?

The schedules of the complete route you are interested in will be uploaded on trenitalia.com on June 12.

But it can be trying -- That is a ballpark number. Not all schedules hit at the same time. Fast trains are generally first and the Regional trains being last. So a little patience is required.

All schedules up to December 11 will be uploaded by June 12, the deadline is the same all over Europe.

The fact that most high speed trains running in summer may be uploaded before June 12 has little interest for the OP. Not only because they are traveling in October, but because they are taking first an high speed train from Florence to Milano Centrale and then a local from Milan to Varenna-Esino.

The easiest thing is to wait for June 12 and see the complete route. Or enter a date before to get an idea of the level of service.

Gotcha! Big thanks to all. I'll try again in mid June

Any idea what is going on with the Trenitalia Rome to Naples 7:00 am train 9501? Every day it seems to be "Travel solution temporarily not available for the selected date" after June 9th. Other time slots are available..

Strange, Italotreno's 7:40 AM train #9903 running the same route is displayed on the schedules only up to July 23.

Both Trenitalia #9501 and Italotreno #9903 trains are scheduled to depart from track #6, it Sounds like works on/close to track #6 made in the morning for safety reasons.