We usually catch the vaporetto from the Fondamenta Nuove. Yes it is definitely worth the trip and I'm trying to remember how long it takes. About 50 minutes, I think but someone here will have been more recently. Always worth investigating the lace workshops and the coloured houses. Spend the day there. If you have the time, visit Murano as well. It's closer (2 stops) and the glass factories are wonderful.