From the city of Florence I recommend taking the SP6 to Sesto Fiorentino, the SP126, the SP1, the SP6 and the SP1 to Pistoia, take the SP9 and the SS66 towards Pistoia.
Then, leaving Pistoia, take the SR 435 that leads to Pieve a Nievole, Montecatini Terme, Massa and Cozzile, Borgo a Buggiano and Pescia.