One other thing to be aware of...if anyone in your party has a Criminal Record, they are inadmissible to Canada. Plus..our laws are more stringent as to what is/is not a Criminal Offense. If anyone has had a run in with the law...yeah, even back in 1970 for a joint...it would be a good thing to call ahead on that item as well.
You don't need your passport to enter Canada..you do to enter the US.
Take heed..those that have already said don't try and hide a gun...border folks are really good at finding those. And, if you have a license to carry, that info pops up the border computer.
And, just to add...these rules apply to those wishing to enter the US, too.
Gary Haupt