Ok Melly, given the criteria you have posted I would recommend that you book the Taormina (on your own) excursion and than take advantage of the trains from Livorno. You do not say how long your are in Messina, but unless its a full day I do not like the train option. If you are in Messina a full day than you could get to Taormina on your own. As to Livorno, you have several options with how to spend your day, but they all would involve getting from ship to the train station...which necessitates a taxi (some use the ships shuttle,..but than you still have a long walk or short taxi to the station). From the Livorno station you can get decent train connections to Pisa, Lucca, or Florence (the 3 most popular destinations). If you are interested in exploring the smaller towns of Tuscany you would need to consider renting a car or hiring a private guide/driver.