I had heard that the Upper Little Susitna has some butt-boating potential so checked it out in July 2007. I started at the Gold Mint trail and hiked up the Mint Valley. I went about 2 miles up the Mint Valley trail, ran a 1/2 mile section of Class II/III and portaged about 1/2 mile around a much steeper section with sweepers and limited visibility before putting back on and running another 1.5 miles of Class III. I took out about 1/2 mile below the Motherlode Lodge as the river started to get steeper and more technical.
At 500cfs this is a spankin packraft trip. At this level, don’t expect to be able to scout a whole lot once you hit the steep section, it is tight and steep, you cannot see the bottom of some rapids from the top, so you enter some blind. The river you see walking up the trail is not the same river that is away from the trail, that part is much harder. Expect technical class IV-IV+, that is continuous.