You're already on an island. Now you go to more islands. Murano (glass, 20 min) and Burano (rainbow houses, 40 min) are on the ACTV water bus network with your regular Venice pass.
Lines 4.1/4.2 from Fondamente Nove. Get off at Murano Colonna. Free glass factory demos.
Line 12 from Fondamente Nove (via Murano). Beautiful lagoon crossing.
Vaporetto with day pass. Murano morning (glass), Burano lunch (rainbow houses + seafood), Venice afternoon.