I think you have the jist of it.   On comment I think may be misstated about passports-

From the US Customs and Border Protection site:  U.S. citizen children ages 15 and under arriving by land or sea from a contiguous territory may present an original or copy of his or her birth certificate (issued by the Vital Records Department in the state where he or she was born), a Consular Report of Birth Abroad, or a Naturalization Certificate.

Also:  U.S. citizen children between the ages of 16-18 arriving by land or sea from contiguous territory and traveling with an adult supervised school group, religious group, social or cultural organization, or sports team, may also present an original or copy of his or her birth certificate, a Consular Report of Birth Abroad, or a Naturalization Certificate.

But then the  "kids" are 18 and over, so have to have passports and pay adult Quetico permit rates.

The previous Q superintendedn - Robin Reilly - commented at Copia several years ago that in Canada, you pay to go camping but if you break your knee, your taxes pay to fix it.  In the US, the camping is cheap, the knee repair not so much.

I love the soliditude of the Q and find it priceless.