Not a backpack, but could be, or integrated into a longer route.
Myself and three other folks did a killer dayhike in the park on Saturday. We hiked the CDT south from 2 Medicine, then ridge walked (on the continental divide itself in places) south to Firebrand Pass. I'm not giving out more info, as good route finding skills are a prerequisite for this hike. Some exposure, some loose stuff, but mostly ridiculous views and easy, solid tundra walking.
Video summary: http://vimeo.com/14778962