If crossing by car you can get by with a passport card. It is a cheaper option if you never plan on needing a full passport. I purchased both so that I do not have to carry the full passport on canoe trips. All the info is available online.

Another thing to check is that no one in your group has things on their criminal record that will prevent their entry into Canada. A forgotten DUI can bring the trip to a halt. Information sharing has made this an important issue. Years ago a person may have entered but not now.