Capri boat tour is pretty fun: Blue Grotto and Faraglioni Rocks. I spent a couple of nights in Capri and think that was better than just visiting for a day. Pretty jammed during the day, but pretty chill at night (reminded me of Venice in that way).
Lake Como and Bellagio was a fun day trip. If I had it to do over again I would have spent 2 more days in Venice and 2 less in Milan.
That's the complete other end of the boot. Not a day trip.
High speed rail is a wonderful thing
Still not a day trip... Even if Como is a favorite spot of mine from my Milan days, where it was actually a day trip. Also not going to go to Venice, Switzerland, Serbia, Croatia, Estonia, Spain, Africa or France.
We left Milan on a high speed rail day trip to the lake Como region. While in Italy we were in Rome, Pompeii, Florence, Milan, Venice, Sienna, San Gimignano, Lake Como, Bellagio, Pisa, and I’m sure I’m forgetting something. We had at least one day trip from every city we stayed at, except Venice. So that would mean from Rome, Florence and Milan. I probably enjoyed Venice the most, but most of it was great and memorable. If I had to drop one it would have been Pisa. It seemed so commercial and downright boring. Perhaps because it was such a long day.