According to the official Canadian website on importing pets, Canadian Food Inspection Agency - Pet Imports
, the only thing you need is proof of rabies vaccination. The rabies vaccination certificate must contain certain, specific, information which is outlined at the above website.
As for firearms, Canada is not like Mexico; i.e., *some* firearms are allowed across the border with the proper permits. To find out which are prohibited, which are restricted, and which are non-restricted, visit the Royal Canadian Mounted Police
Oh, and be sure to take your passports or passport cards with you...you'll need them to get back into the U.S.