We are visiting my son who is studying abroad in Florence. We are want to go somewhere for a long weekend - Thursday (late afternoon) through Sunday. Any suggestions? We have been to Cinque Terre, Rome, Sienna before. Maybe somewhere new. Is Naples too far?
Consider Bologna. It's about an hour train ride north of Florence. Feels like a "real" Italian (not many tourists). Many historical sights and wonderful food.
From Bologna one can take a day-trip by train to the lovely town of Ravenna, though an overnight there would also be good, because it's not a short train ride. Apparently due to its location, Ravenna is amazingly untouristy, considering the beauty of the town and the presence of seven (!) medieval mosaic sites there. Most of them are right in town and very walkable. The last is a short bus ride out of town.
If you have 3 nights and want to see the Amalfi coast (like Positano) go for it.
If you want something closer and as spectacular, try driving down to Val d'Orcia in Tuscany and doing the smaller towns of Pienza, Montepulciano...
If it were me, I'd rent a car and spend the time in Chianti visiting wineries and some of the lovely small towns like Greve, Volterra and San Gimignano.
DD
A long weekend in Venice sounds good to me...
Depending on your interests, either Venice or Bologna. Since Bologna is a university town, your son may, or may not, want to go there. Can't go wrong with Venice, though!