Doing a wine tour in Italy is not as simple or as easy as CA. First, almost all, certainly the better ones, require an advance reservation. Second, some of the average wineries are set up for the bus tours -- big parking lots, wide road leading to the winery, etc. Some of the smaller and more interesting wineries will be accessible via car only. The bus tour will give a decent over view of a couple of wineries. A private car and driver would work better. You should check with the TI on the square (plazza) for wine tours.
We spent five days in and around Florence visit three wineries a day. One thing we did that was great but very expensive was lunch at a couple of the wineries. Many wineries will offer a multi-course lunch paired with their wines. There is really nothing more elegant than sitting on a patio overlooks the vineyard having a five course, nearly two hours lunch with matched wines. Close to heaven and it wasn't W Virginia.