I'm headed up to Northern Ontario about the same time you're headed up to Leech Lake. I've had excellent luck with all white flies between 5 and 8 inches long. The majority of my pike have come from around beaver huts. Rocky points, fallen timber and stumps or big rocks in shallow weedy areas have also produced. Make sure your father-in-law is driving the boat, that way you can get that first cast into a good spot.