Ciao--Tuscany is, for the most part, a "red wine" region. However let's break it into pieces: 1.) if you want the "most famous road" through Tuscany, it is the SR222, so-called "Via Chiantigiana"(the Chianti Route) which runs from Florence in the North to Siena in the south, and goes right through there Chianti Classico region. Again, mainly red wines, but very, very good. AND the scenery is gorgeous...total eye-candy. I can give you many possible wine stops if you wish.
(if white wines are a real priority): To the west of the Chianti Classico region (but still in Tuscany)is the district around a very famous hill town called San Gimignano. This is a highly-visited town and a UNESCO world heritage site, because of the surviving mediaeval towers in the city (look it up.)Around San Gimignano they grow a characteristic white wine called Vernaccia. It is, admittedly, more famous because of its location outside San Gimignano than because of its transcendent quality, but you could nonetheless "check the box" on your desire to taste white wines, while also taking in one of Tuscany's most famous hill towns. AND very pretty scenery. Nearby are two other towns which aren't known for their wine, but might be nice stops on a one-day tour: Monteriggioni (a town fully enclosed by a castle with 11 towers) and Volterra, once an Etruscan capitol. We've been in Tuscany in November. The weather is passable, but the vines are turning incredible colors, much like the autumn in the eastern US (or UK).
So much for Tuscany. At the lower end of the province, along the main Florence-Rome Autostrada, and technically in Umbira, lies Orvieto, a SPECTACULAR town on a high mesa of Tufa. This is a cool town in and of itself, but also has a vibrant white wine tradition: Orvieto classico, a wine that runs the gamut from dry to semi-dry to semi-sweet, and is very pleasant. This is a further drive south, and well on the way to Rome, but also is a possible consideration for you.
Reach out if you need more.