Northern Italy in September

I found Vicenza a much more interesting city than Verona, and don't overlook Padua (Padova) which can easily be done as a day trip from Venice (30 mins on regular cheap Regionale trains).
Something special is Trieste, a well-preserved reminder of the days this city was the main port of the Austrian-Hungarian empire. In my experience well worth the 2-hour trip.
Milan might come as a disappointment. I'd say you better invest that day in elegant Turin. But it depends, of course, from which place you'll be leaving.

Sounds good, so far. Is that 1.5 weeks, e.g. 10 days? It's feasible if you stay in Venice, Varenna, and Turin, but only see Verona and Milan in passing. A few days more would be ideal. It will also help you if you lay this out on a calendar, with hotel nights and train travel time added (although train time for this route is relatively quick).

Is this for 2017 (plane tickets booked?) or 2018? Will you fly into Venice and out from Turin or Milan? That "multi-city" flight booking is most efficient.

This would be a nice honeymoon, and September is usually great weather and slightly less crowded. Is this the number of days you have?

Venice - 3 days, including day of arrival
Verona - 2 days
Lake Como - 2 days
Turin - 2 days
Fly home next morning

Love Venice! If you're flying into Venice, be sure to stay two additional days - so much to enjoy!

We like Verona - Roman Arena, nice piazzas, and since you're on your honeymoon you will want to see the cute set-up for Romeo & Juliet balcony (looks nicer by evening light).

We stayed at Townhouse 70 in Turin - very nice, large modern hotel rooms & excellent breakfast. Good location near the Royal Palace. We were in Turin for 2 days and wished we could have stayed an extra day.