Years ago I took my two kids (10 and 12 year old boy and girl at the time) with my buddy and his two kids (the same age and genders) for a week up on the Albany River with Leuenberger's. Non-stop action for eater size Walleye, plenty of 36"+ Pike and even some nice Brookies in the feeder streams. Miles of beautiful water to explore and a nice beach at the camp. At the time the cabin and boat/motors were in tip top shape.
It was a trip that my kids still talk about and say was their favourite...and since then they've been Salmon fishing in Rivers Inlet BC, flats fishing in Belize, Mexico, & Bahamas, and off-shore fishing in Costa Rica.
I see these days that a 7 day trip to the Albany is under $1500. Nakina is about a 13 hour drive from the GTA.
https://www.leuenberger.ca/