The advertised room was not available, however Jacopo made arrangements to have us stay at another unit nearby which was quite comfortable. I never met Jacopo as he was busy when we arrived and had someone else show us to the other unit.
It is a 10-12 min walk from the main bus station and a 15-17 minute walk from the Santa Lucia train station. We did not find the place easily when we first arrived, we were walking around in the heat for a half hour. It would be better for Jacopo or one of his associates to meet you at a popular spot and then walk you to the apartment.

In Venice, google maps is your friend. You generally want to get lost in Venice, however at the end of the day when your feet cannot take it any longer, google maps will help you find your way home.