"So we could do regional trains from Venice to Levanto. I think this is the longest leg of the trip. So not too sure if we want to add an extra hour but if we are saving $60 EU it might be worth it, especially as we are paying with our low Canadian dollar :( If doing Regional trains then you don't have to book ahead? You just go to the train station in Venice and purchase the ticket?"
Hi Mary. Look on trenitalia.com. Use station names Venezia San Lucia, Levanto, and Firenze SMN, and enter the 'hour' or it will default. On ANY train and route - regional, fast, or combination, you can always just wait and buy your ticket at any station in Italy when convenient, or right before you board. If so, the most you will pay is the 'base' fare shown on trenitalia.com. Check your dates and see what routes and discount fares are offered, if any, then decide whether the discount offered for your particular day is worth it to you to lock in your exact date and time.
Also note that from Venice to Levanto, there are routes via Milan, or via Florence.
"Are you buying multiple tickets or is it one ticket from Venice to Levanto (I understand you would be changing trains but not too sure if they issue one ticket or if you have to buy at each place that you switch)."
You can do either, but in general you are given one ticket which will list all the segments. Enjoy your trip.