My 2 cents:
Venice late January and February can be magical. Remember a crisp, cold Feb AM and stepping out on the terrace @ 6AM to see people getting on & off the vaporetto on the Grand Canal. Big snowflakes lightly falling in the afternoon. Venice is quiet when you get away from the tourist areas but with a light snow a hush surrounds you. Dress right and it is great. Have a great meal at Al Covo.
Personally, that time of year, I'd prefer Sicily or Puglia or even Amalfi but if you are in the north and want to see smaller towns, Tuscany could be good to drive around - Siena, San Gimignano, Lucca... Personally, off the beaten track, I kind of like Marche a lot but Tuscany that time would feel more off the beaten track than at other times of the year. In Toscana, I would find a comfortable cozy hotel or agriturismo and make it a base rather than constantly pack and move. I'd train from Venice and, if you want, spend some time in Florence before getting a car and going to the countryside.
If you want to do the cities (Florence, Modena, Bologna...) skip the car and take trains.