You won't be able to rely on either plane or train slchduees here that far in advance. The train slchduees here in Italy change every June to a summer schedule and December back to a winter schedule. That means the schedule will be changing three times between now and when you want to make your trip. Usually, the changes aren't huge. You can get a rough estimate by looking at the timetables now. However, Italy is upgrading the system to introduce high speed trains and there's a lot of work going on that could affect the trains. Basically, it takes about 7 to 10 hours between Nice and Florence right now. The prices can be adjusted too. Prices went up about 15% in January. The night train (9 hours; no changes required) costs 48 euro for a seat or 78 euro for a berth in a four bed compartment right now. There's another route during the day that takes about 8.5 hours, but requires two train changes for 28.70 euro. The standard fare can be somewhat higher (on the order of 100 euro). Most of the options will require at least one train change.