Traveling from Nice to Siena ( on a Sunday) trying to figure out the best way with least number of changes. One site recommends Nice to Ventiglimia to Milan to Florence to Siena another recommends going through Pisa. First time on Italian trains and a little confused/nervous. Any advice appreciated.
What you list looks about right.
Having experienced taking the trains in Italy which often run behind schedule causing one to miss connecting trains, I'd fly Nice to Rome (easyJet ) and then catch the bus (flixbus) direct to Siena from outside Rome Tiburtina train station.
Or break the trip up by staying somewhere halfway. You might be forced to anyway if one train is late causing you to miss a connection.
According to Rome2Rio, bus 492 departs Nice from the Vauban station at 8:50 AM arriving in Genoa at 11:30 AM. Unfortunately, there is no luggage storage at the bus station in Genoa but you can store bags at the Genova train station: Piazza Principe, 16134 Genova GE, Italy that’s a 5-minute walk. You could find a great spot for lunch and turn it into a siesta.
Bus N552 departs Genoa (Fanti D’italia/Principe Bus Station which is the same station you arrived) at 4:15 PM arriving in Siena at 9:15 PM.
That makes it over a 12 hour journey.
Even the flying route is rather tortuous. Be at the airport at least 1 1/2 hours before flight, 1 hour flight, take the train to Tiburtina, which will get you there 1 hour after you land if you are checking luggage, 1 hour average wait time for the next Flixbus, then a 3 hour bus ride to Siena. 7 1/2 hours give or take an hour.
https://www.trenitalia.com/en.html
Enter the following:
From: NICE-VILLE
To: SIENA
Choose a date (if in the far future use a Sunday in this month)
enter a time as early as possible in the morning.
There are many solutions. They require at least 4 train changes (5 different trains) and a total journey time of over 8 hours.
It's better than the bus for 12 hours, and not really worse than flying to Rome (which, as noted, will take you almost 8 hours from the time you get to the airport to the time you arrive in Siena using planes, trains, buses.
If you feel capable of driving, you could take a train to Ventimiglia and rent a car, dropping it off after the Siena visit. Your route would not involve passing through urban areas on local streets.