the best trips will be for you to decide. if you have good weather and like lake scenery.. lago di garda.

sirmione, or go further up the coast.

otherwise, there are soooo many lovely places that have been suggested.. just pick one, have a nice meal and stroll, and make plans to come back.

vicenza, bergamo, marostica, ..

you will enjoy it all. none of these places will disppoint you, i am sure.

but it looks like your week has turned into four nights?? 2 in venice, and 2 in verona?

i would leave venice very early and stop in vicenza on way to verona.. not to backtrack.