Tips on the Ferrara,Venice, Verona, Ravenna area

Ravenna can be done in half a day. Venice will be cold and damp. Dress warmly and plan a LOT of indoor activities.

What would be some good indoor activities?

Verona is a very nice place,, with a Roman colosseum (still in use for concerts), several museums, gorgeous surroundings and a river on 3 sides of town.
Ravenna did not appeal to us at all and we would not recommend that you waste time there, tho others have said they enjoyed it. We think that, aside from Milano, it is the place best avoided in north Italy.
A city not often visited but interesting , is Vicenza.
We would think that if your son is studying there, that he knows quite a few places and would be willing to tell you about SOME!!!

The Doges Palace is about half indoor and half outdoor. See if there are any concerts or other performances. Other museums are typically indoors. Any Venice guidebook should give you a lot of options. The Blue Moon, Lonely Planet and Rick Steves' guides are some of the best, typically.

Yikes! I don't know what the previous poster was looking for in Ravenna, but I have to disagree in strongest terms. Of course, it all depends on what interests you. Ravenna is home to the best Byzantine mosaics and sculpture outside of Turkey. There are more sites than can be listed here. We recently spent 2 nights, i.e, 1 whole day, there; and we walked our feet off. We had been there before and revisited only one place. The old city is pedestrianized (locals ride bikes), and you can pretty much walk to everything except the church of Sant'Apollinaire in Classe. It also has the usual complement of piazzas with cafes and restaurants (many good ones) conducive to relaxation and people watching. You can e-mail me if you want the name of a great and reasonably priced b&b within the walls or to know more.