The Madrid rest stop is certainly going to make your kids happy. It’s only 1 hour or so from Quebec City so it makes a great final pit stop.
Even better, it has a St Hubert and a McDonalds inside so a good variety of kid choices. Warning, outside there are numerous large dinosaur statues that are so cool your kids will want to take pictures in front of each one. It also has a playground for the kids up front. During nice weather it has nice picnic tables to enjoy the weather.