Milan Itinerary question

Both Venice and CT are too far as a day trip -about 3 hours each way

Would be like visiting NYC and taking a day trip to DC or Boston
Makes no sense

If you want to visit those 2 locations plan a few nights in each otherwise you are there mid day right smack in the crowds and heat

Day 2 - guided tour to Cinque Terre
Day 4 - guided trip to Venice

Have you looked at how much travel time is involved to get to/from these destinations from Milan?

The only good thing I see is that you have a 'rest' day in between.

Had you asked before you booked things, I suspect the advice would have been to choose either Venice OR Cinque Terre and spend at least a night.

Hope you are used to heat and do not wilt easily. Accept the fact you will be a part of the peak crowds of 'day trippers' on those days.

There are direct trains from Milan’s central station to Venice (Venezia) S. Lucia station (end of line) that takes 2h 30m: https://www.trenitalia.com/en.html. You don’t need a guided tour all you have to do is turn left when leaving the train station and follow the crowd that will take you to Rialto Bridge and St. Mark’s Square. I would reserve tickets for St. Mark’s Basilica before going or you’ll wait in a very long line.
From St. Mark’s Square take a vaporetto bus back to the train station so you can see the palaces that line its Grand Canal.

The Cinque Terre takes longer as a day trip, but there’s a direct train departing at 6:10 AM arriving in Monterosso at 9:05 AM. From Monterosso you can take a direct ferry to Riomaggiore departing at 9:30 AM arriving at 10:15 AM. From Riomaggiore you can take a train to Manarola, Corniglia (then bus to top of town), Vernazza (good place to eat) then to Monterosso. You can then take the 6:55 PM direct train from Monterosso to Milan arriving at 9:53 PM.

Enjoy the Bernina Express!

CT and Venice require too much transportation to be valid options; and Venice does not lend itself to day trips. I suggest self trips by train to Bergamo and Torino [being sure to visit the Cinema Museum for its very creative presentations]. For a day trip you double the train times and add a couple more hours for the 4 trips to and from stations. Lake Como you take the train to Varenna, which takes an hour.

Plan for the CT posted above is absolutely absurd.

Thank you everyone! I really appreciate your advice. I think we will skip the day trip to Cinque Terre.

Do you think two days will be too much in Milan? Could we see the main sights in one day?

Family doesn’t want to visit museums.

Could we see the main sights in one day?

Yes if you don't include the Navigli food tour. Reserve tickets for the The Last Supper before leaving home.

I would do 2 days. The things I think you do should do:

Visit the Duomo and try for the rooftop walk. This way, you’ll get to see some of architecture/art up close and you will get nice views of the piazza and area below.

Even if you don’t like to shop, visit Vittorio Emanuale shopping center. Right near the duomo. The architecture is pretty great and it can be done in less than 30 min if you don’t shop.

See the Lat Supper. This is Leonard da Vinci!!!

Brera Art Gallery. Don’t go if you’re pushing your luck. :)

Sforza Castle.

Navigli scene. Seems like you’ve got that one covered.

La Scala. I haven’t been in but I saw it from the outside so I could tell people at cocktail parties that I had.

As far as the Navigli, I would not skip it, but I see no reason for a tour. It's several canals, with bars, gelatto ships, and restaurants. We did our usual approach - start at one end, walk around, look at menus, pick out one for dinner. Your daughters will love it, as there are many other young people. Be your own guide!

We did 3 things in Milan - 1) Duomo and environs (4-5 hours), Sforzesco Castle (4-5 hours), Naviglia. We stayed 2 nights.

We didn't do the Last Supper.