coldestwinter
If you are flexible....I'd play it by ear.....when conditions go epic...make the trip. Sled Den
http://www.gaspe-snowmobile-adventures.com/snowmobiling-about-us.html
has a blog you can watch which will give you conditions on the north shore of Gaspe as they evolve (some of the better riding areas). I can too.
Since Gaspe is close to sea level, every year is different and early season is always somewhat unpredictable. 2 years ago we were riding November 8th. Last year...Jan 10th...so it depends.
Realistically, mid to late December is a safe bet for snow but it really depends on how the year sets up. This year looks normal so far, albiet overall preciptitation is lighter than usual for the entire east coast so don't know how that will play into winter snowfall.
If you come to Gaspe, include Murdochville in your plans. It's a PITA to get to but is smack in the middle of the snow belt and has backcountry in every direction. Hotel Copper has a sledders special and you can park ur sled right at the front door. It's not high end by any means, but a solid place to stay. Amqui, New Richmond, Carleton, Matane are other solid options. Do you homework first.
Hope you make your trip.
OTM