We will be in lake Como ( Verenna) and then CT (Monteroso) in late April. 4 nights in each location. Any must see, eat ,drink, do ideas?
Be sure to visit this gorgeous Villa. https://en.wikipedia.org/wiki/Villa_del_Balbianello The grounds are lovely as are the views of the Lake.
We stayed in Bellagio for a week. Lovely little town to wander around. Be sure to have the traditional Milanese dish; osso bucco with saffron risotto.
You can't go wrong just getting on a ferry and stopping at the little towns along the lake to explore.
Bellagio is probably the most visited town, but anywhere along the lake is good for some walking around.
I like the city of Como, especially for silk shopping.
With 4 days on the upper portion of the lake perhaps consider a car rental and exploring the western coast that is not served by rail. I've driven that route and it is wonderful.