No George, that is an assertion, not a definition. 
It would of course depend on how extraordinarily “favorable” the conditions were – which would, as I said, “depend on the prevailing conditions of the sea in question.”
The Roaring Forties get their power from the Earth’s rotation. Nullifying that effect, for any significant period of time, would require playing with the laws of physics – a miracle, by most definitions.
This would be particularly true if the conditions needed to be sufficiently favorable that a bark canoe would not be swamped (which is likely to happen in even the gentlest of open-ocean conditions).
I never said so. However, going in a non-straight line will necessarily increase the distance.
It is not clear what your map is of – it does not appear to be of Bass Strait and its islands:
Island-hopping would lengthen the time of the overall journey, and thus how long favorable conditions would need to be maintained for. It also cannot decrease the size of the largest ‘leg’ below the largest gap between the islands in the journey.
It would also increase the calorie-cost of the crossing – which in turn raises the question of whether these bleak, rocky, uninhabited islands would provide a source of easily-accessible carbs.