I would definitely call the crossing in which you plan to cross at, Canadian immigration, not US, to ask what to do. If you believe your record was thrown out, pardoned, or whatever, bring your arrest record for proof, or they will turn your around to do just that. I think sometimes if so many years have past since your arrest, they may let you in. If you have a criminal record you will probably need a criminal waiver to enter Canada. I suggest having a passport or passport card so they know what country you are a citizen of, if not bring a photo ID and birth certificate if your a US born citizen. You can bring as much booze to Canada as you want, you will just be charged tax or duty on anything over your tax free limit which is usually 1 bottle or 1 case per person. If your unhappy with your experience there, talk to a manager and get a comment card. Ive filled out a comment card and its effective....
Do your research not (I heard from a buddy that...) or call them with questions.