Wow, great old video, thanks for posting.
A couple things on it. The upper part of the Youkon (Yukon) River that they showed on the map, is actually the Tanana River, a very large tributary of the Yukon. There is a glacial river that is tributary to the Upper Tanana River, the Robertson River. My remembrance is that the Robertson River was named after a guy that was part of a US military expedition that mapped & traversed the Upper Tanana early in the last century. Can't remember the guys full name i.e. if Young was with the Robertson that was on the first official expedition, or if a different Robertson. I'm not a Young historian but I've been on the Yukon, Tanana, and Robertson a fair bit and have some history of the area.