Saturina base

Saturnia is NOT a good base for all of Tuscany. It's in Maremma, therefore too decentralized to the south. It will take you 3 hours to drive to Florence from there and at least 2 to Siena. You should choose an area along the freeway between Florence and Siena. Then you could go to Saturnia for a day trip from there or maybe spend a night or two in Saturnia. But basing yourself in Saturnia will make it difficult to visit most of Tuscany, except for the Maremma (province of Grosseto). I presume you have a car. Because if you don't intend to have a car and relying on trains and buses, then you should stay in Florence. Saturnia is a long haul to get to if you don't have a car.

one of my ideas was to go to Saturnia for one night after Sorrento then find a villa in the Tuscany region and do wine tours and day trips. Thank you so much for your assistance

Your plan works. But for your villa in Tuscany look for something between Florence and Siena, better if close to the freeway. That area is the most popular with American tourists (albeit more expensive) because it's very central and more efficient for day trips to the various Tuscan top destinations.
The more decentralized parts of Tuscany like Maremma in South Tuscany or the Casentino Valley and Tiber Valley in Eastern Tuscany are more popular with repeat visitors from Germany and other Europeans, because they go to Italy every year and have long vacations, so they have seen most of Tuscany in previous trips already, and they don't need to be in a central location to go all over the place in Tuscany. They just want a place to relax. But for most Americans who don't visit as often and also have very short vacations, it's better to stay in a strategic central area so that you can maximize your short time there. That strategic area is between Florence and Siena.

Thank you so much for that nugget of information :)