One word of caution.. in a closed thread somewhere a poster with a criminal history (DUI) tried to enter Canada and was turned back.
Though the standards are a bit different here in the US.. A Criminal history may get you turned back coming this way as well.. and some times that includes DUI.
There is a whole lot more I could type.. but wish not to.. Rather I will point out that discussing this issue is pointless NOTHING we say or type here will change who is and who is not allowed to cross the border.
Check with the proper Government agency IF you have anything even 40 years ago, that might be an issue.... They can tell you if you are wasthing your time or not.. (I, on the other hand can not give that information)
One thing that could be added:US Customs, border patrol or Immigration, One of those (not sure which) is the right agency to ask.