If you only have 4 full days, I'd stay in Venice. Maybe a day-trip to Verona or somewhere, but I wouldn't move to an entirely new place and hotel in that short amount of time.
With more time, I'd be interested in seeing the Dolomites or going to Paris or Rome or....

We rented that aparatment in Venice for a the second week of June -- (yes, last month).

Too good to be true? I still think it is way under priced (don't tell the owner I said that). The location and the building were amazing. It is a wonderfully done conversion inside a remodeled building, done with great taste and quality. There a couple of really grand and interesting antique furniture pieces. The two sofas were comfortable.

The only negatives might be that the "loft" bedroom has a fairly low ceiling -- maybe about 7 feet, but there is also a step up onto the "bridge" to the bathroom there and a low beam that takes some getting used to not to crack your head. We both managed to hit it a few times. The steps going up to the loft were very odd, but clever. Because it is so steep, every other step is half deep and half wide, so as you go up, every other step is wide for your left foot, and the steps between the others are wide for your right foot. Takes a bit of getting used to.

It was nice having two full baths (both with showers).

There is really not a kitchen, just a tiny fridge, sink, and microwave -- but that's fine for us.
The air really worked -- it has two units, but we only turned one on.
The building has an elevator, but we preferred walking up and down the one flight on those grand red carpeted stairs.