I recommend Lorenzo's place as an excellent place to stay while you visit Venice.
His apartment is well-located, about a 5-minute walk from the San Toma vaporetto stop. Or, it is about 5 minutes walk to the Frari Basilica, 10 minutes walk to Rialto Bridge and 20 minutes to St. Mark's Square. Entry is by keypad, with the code given to you on the day of arrival. His apartment is on the 2nd floor (American), up a flight of "regular" stairs (not steep at all). The apartment was clean and comfortable, and the views of the canal from the living room are especially lovely each morning. Lorenzo was very responsive, always patient in answering all of our many questions. Thanks Lorenzo!