General informations + trip planning here :
http://www.chic-chac.ca/Or here :
http://skichicchocs.com
If you're going to do freelance touring, your best bet is to book a lodge near the park (in Ste-Agathe-des-Mont for example) and drive to the mountain you want and then earn your turns.
Check out Mont-Logan, Mines Madeleine and Le mur des Patrouilleurs. Those are where the best powder and steep lines are. There's not so many spines and huge cliffs. It's most likely open terrain with pitches.
However there is a ton of mountains in the park so try to find a good map with all the mount and set an itinary! You can always hire a guide for like 2 days and then go all by yourself, unless you plan doing long tours.
Did you also check out Les Monts Groulx? It's not in the same region at all but there is some really nice touring to do there aswell. (It's a long drive, but it's at least 1 hour away from any population, it's a real step into nature.)