-- Last Updated: Oct-07-12 9:06 PM EST --
Surely you know of the Yukon River Quest that takes place every June, and also the Yukon 1000. While the YRQ has up to 100 entrants, the newer Y1K has had much fewer (though I prefer the longer race) You might have some luck posting on the YRQ web page, folks are always asking about transporting their boats up there. http://www.yukonriverquest.com/
I too am tinkering with the idea of paddling the entire length of the Yukon. I've paddled the YRQ and the Yukon 1000 mile races (twice for the Y1K). And as you know, once in it's grip, you cannot escape the call of the Yukon. One way or another, I will return to the river.