No big deal at all, just show your passport or enhanced drivers licence, answer their few questions and you are on your way. Only time you may have trouble that I have heard is if you have a criminal record.
I can guarantee you will not be disappointed, if you decide to go let me know and we could meet up on the way and go together. I'm about 3 hrs north of Detroit.
It is in New Hamburg Ontario, less than 3 hrs from Detroit. There is a post all about it on here, a really good time. Woodward in my opinion is too big and too busy and the majority of the cars I don't really care about.