I can't help you with cabins but when I first started riding in Quebec we stayed at the Colibri in St. Foy. There is also the Quebec Inn in the same town. It's about 15-20 minutes to the Old City. Try to plan on early February & take in the Winter Carnival. The Colibri is very dated but it has everything you would need. (Bar, restaurant, locked parking for sleds, close to gas & stores). The Quebec Inn is much nicer (more expensive) but does not have locked parking for sleds and they have had problems there with sleds being stolen. That may have changed as I have not been there for a couple of years. There are multiple trails from that area. My first 8 years we rode from there for a week at a time and always found plenty of places to go to by sled.
Good luck, where ever you go you probably won't be disappointed.
Denis