Good points Jimbo.

As a hobby, I've been looking for the "route" that MacKenzie must have followed to travel from Grand Portage through to Athabasca, then the Great Slave Lake to pick up the Deh Cho, aka The MacKenzie river for his ill-fated trip to find the Northwest Passage.  Brian Castner's book, Disappointment River partially covers his own voyage and MacKenzie's story which is fascinating. Peter Pond was quite the character as well.