Fodor's Travel Talk Forums - Drive or Train from Zurich to Florence?

We are planning a trip to mostly Italy + Switzerland flying into/out of Zurich on Oct 1 for 12 days. We want to visit Interlaken for a day or so then go to Florence for 2 days and then drive to Tuscany and Cinque Terre .

Initial thought was rent a car in Zurich and drive to Interlaken, Florence, Tuscany, Cinque Terre and return to Zurich enjoying the drive through northern Italy and Switzerland.
Now I'm wondering if we'd be better off taking the train from Zurich to Interlaken then to Florence pick up a car after Florence and drive to Tuscany and Cinque Terre returning the car to Florence and train return to Zurich.

Trying to weigh the pro's and con's? I assume it could be a beautiful drive from and back to Zurich and we'd have the freedom of schedule to go when we want , etc. I know we don't need a car in Florence but we could park it for the two days there. So, is it worth driving with possible weather issues to experience what I assume could be a scenic drive?
Thoughts? Best Driving Routes if we drive? Thanks!