Highly recommend this hike! It's short and sweet. The view is great and it is not a very crowded hike. I recommend going here if you go to the nearby Parc de la Gorge as well, it is about 25 minutes away.
We came from Parc de la Gorge on Ch de Baldwin-Barnston road, which leads you to the Parc Harold F Baldwin area. Turn left onto Ch May and park your car in the parking area that is next to a small shop/cafe. There are signs at this point. Walk up the hill a bit until you reach the blue Mt. Pinacle sign and the trail on the right of the road. The hike up took us about 20 minutes to the awesome view. To get back down just retrace your steps. There is an intersection at one point about 3/4 of the way up, we just kept right but the other option will also take you to the top.