The western section of Les Trois Pignons generally run parallel to road D16, and are easily accessible from Milly-la-Foret. If you travel to Fontainebleau and stay at "La Musardiere" (a popular climber's campground), these areas are easy to get to. Some areas are much more popular than others; La Roche aux Sabots is the gateway to other popular areas like Le Cul de Chien, so it gets loads of traffic. Still, there's plenty of climbing for everyone.
Getting There
These areas are closer to the town of Milly-la-Foret, Arbonne-la-Foret, and Noisy-sur-Ecole than they are to the town of Fontainebleau. The best thing to do is purchase the IGN map for Fontainebleau and go from there...