For this one, we opted to rent bikes and do a self-guided tour. My parents joined us (after our morning of kayaking), and we stopped at four wineries; Pellar Estates, Caroline Cellar, Pondview and Pillitteri Estates. While we mostly enjoyed the wines we tasted, the biking was the part of our day we enjoyed the most.
Details: We rented our bikes from Zoom Leisure Bike Tours and Rentals, details here. We had a great experience with them, and liked that they had a variety of bike styles so we could each picked what suited us best.