Just a note for Killarney, on the plus side... even though it's overused and crowded, if you can find a place or a time to beat the crowds, the geology of the place makes it different and worth seeing. The quartzite ridges are very old remnants of mountains formed about a billion years ago and the world's hardest rock type that exists on scales large enough to form mountains.
If you spend time up in the rocks you can see all sorts of interesting features, the most obvious being glacial smoothing and scratching that still is clearly visible in quartzite, since it weathers away very slowly. The less hard granite outcrops show scratching less distinct, and the softer gneiss, which forms most of Georgian Bay and the French river, has weathered down enough over ten thousand years to eliminate the smaller scratches.
Plus all sorts of other detail which I'm not going to get into here too much... Killarney is rising due to glacial rebound and that opens up deep cracks in the quartzite ridges, still opening so don't fall in. And much older cracks which filled with molten magma when the rock was much deeper below the surface, before being weathered down. And raised cobble beaches since the Georgian Bay shoreline is rising about a foot per century... OK, stop there, you gotta get out of the canoe to see these things.