Recommendations for Northern Italy

Padova as a home base for Verona and Vicenza would be great. It's a charming town. We haven't been to Vicenza but have been to Verona twice. We really loved it. Lots to see and do but it's not completely overwhelmed by tourism. It's a fully functioning city in its own right.

It would probably be best to prioritize your interests: relaxing by the lake or seeing some great Palladian architecture (Vicenza) in order to decide where to go. As Michael mentioned, Padova would be a great base for visiting Verona & Vicenza. You could easily do Verona as a day trip one day and Verona as a day trip the next day if Padova is your base. Milan is only 3 hours away from Venice so you could squeeze in a night in Milan and a night or 2 in Lake Como, but it would be rushed to do all of the above. If you are flying out of Milan, it would be easier.

Fly into Venice and fly out of Milan. After the cruise spend 4 nights in Padova and 2 on Lake Como. Get a later flight out of Milan to give yourself time to vet to airport. Might be worth it to hire a taxi. Rick has one recommended in his book that will take you from Varenna on the lake to Milan airport

John, since you only have 7 days: An option for working in a little lake time without spending the time to go all the way to Como would be Lake Garda. I've not been (will be going in a few weeks), but I've heard really good things about it, and it's an easy day trip from Verona. It would allow you to spend your whole 7 days in the Venice area, which would be the best use of your time, given such a short stay.

You only have 7 days, you can't spread your trip over such a large area. You should concentrate on the North East only (Veneto, Trentino) and forget about Lake Como and Milan. Besides Venice, which you have already seen, my favorite city in Veneto is Verona. Padua would come next in my list, followed by Vicenza and its Palladian villas. I think most Italians would agree with my ranking.
Lake Como can be easily substituted by Lake Garda, which is only minutes from Verona. If visiting a lake is in your plan, you could choose Verona as base and visit the lake from Verona. If you prefer to stay overnight on an idyllic lake shore village, the most beautiful part of the lake is the north lake, where the lake narrows between the Prealps. Limone, Malcesine, Torbole, Torri, Gargnano, are the prettiest towns in the North, IMO. Riva is nice too, a little bigger. In the south, Sirmione is gorgeous and the top popular destination, but in high season it's overrun by tourists more than Disneyland ( so be warned). If you like mountains, the Dolomites are absolutely gorgeous and nearby. With limited time however you may not be able to squeeze all of the above. The Dolomites can be covered more efficiently with a car, although buses go there. The Val Gardena is my favorite area in the Dolomites.

I second Roberto's advice. We liked Verona by far the best. Haven't been to Lake Garda yet but want to go! Robert also has suggested a good plan.

Thanks to everyone for some great ideas as I plan for next May.
John

Five years ago we spent several nights in Padua as a base for touring. We visited Venice, Vicenza, and Verona, traveling by train and spending a full day in each city. Journeys were about an hour or less each way, fares pretty cheap. In Padua we stayed at the Hotel al Cason and liked it a lot. Family run, very nice people, friendly and helpful. The hotel is perfectly situated to walk to the train station in 5 minutes or find a bus into town, and worked very well for our day trip needs. The hotel has a small bar and resturant which was convenient. Also a small outdoor space, though trains run behind it, never a problem. Evenings free in Padua to walk the Prato, University area, lovely town center and the remarkable Scovegni Chapel...pricier tickets for small groups in the late evening was worth every cent in my book. Padua doesn't get much press, but we found it pleasant and a perfect fit for our travel needs in the area. Have a great trip.

I agree with Roberto on choosing Verona over the other cities that you mentioned. If you have a car, the Dolomites would be another wonderful trip to make. Whether you stay in Verona or just visit it, be sure to have carpaccio in one of the restaurants that serve it. We ate at one on the main square, where we were taken by friends who lived there. It was a treat.