I need help with a northern Italy itinerary.

kellirdh, start by figuring out how many nights you actually have in Italy. What does two weeks mean? Assuming you are flying from North America, you will lose a night flying overnight to Europe. Leave Sunday and return Sunday two weeks later- that's 13 nights in Italy + one in the air on the red eye flight to Europe.

If you want to see all of these places, you can't practically base in one of them and see the others - they are much too far apart. If you want to visit the Cinque Terre, Milan, Lake Como, and Venice (don't think you have time for Switzerland), you will be have to stay in five different places. In theory you could day trip from Milan, Lake Como, and Venice - from one to the other two - but you'll lose so much time getting back and forth that it's just not going to be worth your time. You can take day trips from most of these places to nearby towns, though

Plus, you'll lose a day each time you switch towns. The trains don't take all day, but by the time you check out of one place, get to the train, take the train, and get to the new hotel, you'll lose most of the day. Changing cities is time-consuming and can be draining too, especially for a family of five.

There's no point in flying into/out of Florence unless you plan to visit Florence. Milan and Venice will be the most practical to fly into. Pisa might work if you can get a good flight in/out and start/end nearby at the Cinque Terre. I don't know what kind of flight connections you can get from where you are starting out.

Let's say you fly into Venice and out of Milan. If you do have 13 nights, then you could do:

Venice (3 nights)
Lake Como (3 nights)
Milan (2 nights)
Cinque Terre (4 nights)
Pisa, Florence, or Genoa (1 night - only if you can fly out easily)

Or you could do:

Venice (3 nights)
Lake Como (3 nights)
Cinque Terre (4 nights)
Milan (3 nights)

Your day getting from Lake Como to Cinque Terre by train will be a pretty long day with connections this way.

Personally, I didn't care much for Milan or find it very interesting, and I would probably avoid if unless it's your best option to fly into/out of. Florence is a much more interesting town in my view, even if you aren't into museums, so if you could fly into Venice, out of Florence, and do that long train swing from Venice to Cinque Terre (with a detour to Lake Como on the way), that might simplify things. But maybe Milan is a place you want to see.

As mentioned above those regions are not exactly close and Milan is worth maybe a day, maybe. I'd suggest leaving out the CT as it pulls you too far west. From Milan you could visit Lake Maggiore and stay up in Locarno which is Switzerland and accessible from Stresa. Train from Milan Centro to Stresa. You could then visit Lake Como which I like more than Lake Maggiore. From the lake region you could train to Florence via Milan and then from there head to Verona (Lake Garda) or the Dolomites then to Venice

Hi, just adding to what others have said, IMO Milan & CT are the least interesting, the latter because of the crowds. I hiked CT extensively years ago, mostly on the very high trails to avoid the crowds & 3 nights was more than enough. Unless you want to see the Last Supper in Milan, but that should only take part of a day. That would leave you Lake Como, Venice, a jag up into the alps & perhaps Florence, if you haven't been. There will be some excellent advice about how to access the alps from Lake Como area if you ask, hope you have a great trip!

I'm not certain why others are dunking so hard on Milan, but to each their own.

Fly into Milan, spend one full day there (2 nights). Easy train to Varenna, stay 3 nights.
4 hour train ride to Florence, stay 4 nights, include day trip(s) from this base.
Fast train (2.5 hrs.) to Venice, 4 nights. Fly home from Venice.

Feel free to bounce days (fewer in Venice, more in Milan, etc).