I have researched this route and discovered that I will need to go from Nice to Ventimiglia on a regional train with tickets bough the day of travel.
Where I am stuck is with routes from Ventimiglia to Florence. We can do a 6 hour journey doing the following: Thello train to Milan (3:30 train time) and then buy another ticket from Milan to Florence on a Frecciabianca (2:48 train) . OR I can do a 4 hour journey with the following: Ventimiglia to La Spezia (2:20 on regional train) then La Spezia to Florence on a Frecciabianca (1:09 on train) with a stop in Genova.
My dilemma is that going through La Spezia looks like such a pretty route along the coast but that much time on a regional train does not sound comfortable and we are traveling with someone with a bad back. The other route, although longer, looks more comfortable and that Milan Train station looks so pretty.
All Italian train tickets, even for the Thello train, looks like I can purchase on the Trenetalia website and if we buy far out enough the cost is about the same. Has anyone done this route and what did you do? Travel dates are in May and we will leave Nice early and plan to arrive in Florence around 1-2Pm. Thank you for any input.