Alessandra and her sister made us very welcome and were very friendly. Breakfasts were particularly nice. The apartment is on bus line 12 which will take you from Mestre to Piazzale Roma, the bus terminal in Venice, in 15 min. The vaporetto terminal is by Piazzale Roma as well. Take water boat nr 1 or 2 which will take you the length of Canal Grande all the way to Piazza San Marco. Buy a 10-trip card (valid on both buses and water boats) rather than a time-limited one because you are not likely to travel enough each day to make it worthwhile