Did this yesterday with some friends...around 400K. Leisurely pace on the way out (highway 2 until Brighton) and then poked along through the countryside, lunch in picton, a visit to the cheese factory for ice cream, stopped at Lake on the Mountain for some photos....ferry ride across at Glenora and then some more countryside up to Napanee. Flat topped the way home, but the reality was that despite leaving at 9AM it was about 3PM when we hit Napanee, so if we had poked home on the sideroads we'd have been home well after dark...and given how chilly it was supposed to be we opted to express home instead.
Beautiful ride, though.