just by the way, float planes use 3 mile lake as a landing pad - they fly in tourerists to ballast those fishing boats you'll see

I've gone down the Malign to Lac La Croix to Namakan R and then up Quetico River to Beaverhouse once - don't recall any campsites on the Quetico R.  I'd add another recommendation for going down Namakan and up the Quetico R - campsites on West end of Beaverhouse are hard to find