For the Explorer category, Strange Things Afoot at the Circle K selects David Thompson, a geographer who single-handedly mapped a full fifth of North America with such accuracy that many of his maps were not improved on until satellite mapping was introduced.
He worked as a trader for first the Hudson Bay Company and then the Northwest Company, establishing trading posts along his way. He also helped map out the Canadian/American border west of Lake Superior. All of this with many of his 13 children following him around. He and his wife were married for 58 years - the longest known pre-confederation marriage in Canada - though unfortunately they died in poverty and obscurity.
It wasn't until Joseph Tyrrell (the famed geologist/paleontologist) found his journals and advocated him as one of the greatest land-mappers ever that he got his due. His contemporary explorer, Alexander MacKenzie, considered him a vastly superior geographer and Tyrrell lauded him as the greatest land geographer who ever lived.
Here's a great writeup on his life and work:
http://www.davidthompsonthings.com/geog1.html
Unfortunately, no historical image of Thompson exists, so here's a postage stamp.