I think it all depends on what you are in for. The problem with the lakes around the crack is that they are very difficult to book. They are stunningly beautiful, but busy and good luck getting in on a summer weekend unless you got onto the booking site 5 months prior to your date. You might be fine booking in the shoulder seasons, however. There are only a few sites on each of those lakes.
The northern section of the park is a lot less busy, and has great fishing if that is your thing. If you want to see those LaCloche hills, you could try to head as far south as David Lake and nip on up to the Silhouette Trail from it's western bay , but then you would have to contend with that nasty portage between Great Mountain and David. The Bassoon, Bear, and Fish lake areas are beautiful, not crowded and have amazing fishing. We did the northern route in the second week of august last year and had our pick of amazing campsites on each of those lakes.
https://www.canoedaddy.com/Killarney-North-6-Days/