If you want to visit the Biennale Barbara's place is ideally located. It's about 10-15 minutes from the Arsenale, 15-20 minutes from the Giardini and about 10 minutes from the Lithuanian Pavilion.
It's a very cleaned well furnished apartment. It was really like staying at a friend's place. This is one of the best airbnb places I have stayed at. Barbara is very kind and communicates really well. She even picked me up from the water bus stop at night and took me to her apartment. I highly recommend staying here.