Thanks for your message, I’m glad to help!
First time in Italy? I would certatinly add the amazing and unique Venice to your trip 🙂 This city on the water is beautiful especially during this time of the year, very atmospheric.
I would instead skip the Cinque Terre, that are better visited during summer time.
After your 2 days in Venice I would take a fast train to Florence, stay there for about 2 or 3 days, then rent a car and start to to explore Tuscany and its many attractions.
This is an example of a 2 weeks stay in Tuscany, just to give you an idea of all the sights you might visit. As for places to stay I would probably make your base in 2 different destinations, one in the area of San Gimignano and the other south of Siena, in Val d’Orcia.
San Gimignano is a good base and makes good for these day trips, and Val d’Orcia is a another good starting point, also to visit southern Tuscany. At the end of this post, at point 4, all the day trips you can make from there.
Take a look and for any further question, just get back,