Pattie, You might want to simply buy a 36 or 48 hour Vaporetto pass which gives you unlimited use of all the Vaporettos. You can find info and the current prices at
http://www.actv.it/english/nav...na=tariffe_vaporetto
You can than use the vaporettos to get to Murano, Burano, Torcello, Lido, or to get around Venice. Those multi-day passes are not cheap (48 hours is 28 Euros) but keep in mind that a single vaporetto ticket is 6.5 Euros.
Hank