If all else fails troll deep cranks at drop offs and points--deeper fish seem to be less affected by cold fronts. Also troll for trout in the basins on wind swept side. Sometimes ya never know...I've had some of my best days during cold fronts where the fish were not supposed to be biting.
This dip in temps is only 5 degrees F below seasonal norms and its right back above normal by Tuesday. Personal opinion.....marginal if any affect. For early June in Quetico that's a money forecast. Go get 'em. Negative thoughts will not produce positive outcomes.