A non-resident of Canada visiting Ontario requires proof of citizenship: birth certificate, drivers license or passport.
You are allowed to bring a 40 oz. bottle of liquor or a case of beer, and one carton of cigarettes per person.
If you are bringing children under the age of 18 bring a letter of authorization and proper I.D.
You are allowed to bring a reasonable amount of personal effects, supply of food and a full tank of gas. (Reasonable means enough for your personal use during your stay in Canada).