If you're in the area you should absolutely make this a part of your excursion. It's completely walk-able and much smaller than I envisioned looking at the map. There is plenty of parking and a flat all day parking fee so you don't have to worry about time constraints. We also saw a number of buses and stops right at the entrance so it may be something to look into if you do not have a car at your disposal. The park provides great views of Montreal so grab your camera. The lake area has paddle boats available for rental. If you forgot a water, there are vendors and spots to purchase a bottle. It's a walk in the park and not a hike so good for people of a all ages. :)
Tips: Great spot to bring and have a picnic. Also, may be worth coming at sunset to see the lit up cross and skyline. I will most definitely do that next time.