The Cottonwood is an 80 km (50 mile) partial loop in Kluane National Park. It crosses two alpine passes and passes through a wide range of terrain with some stunning views. Mid-August to early September the fall colors can be spectacular.
The trail consists of rough 4x4 road, abandoned mining roads and singletrack. Most of it is runnable if you have the legs.
It is remote and sees few hikers each year so can be grown in. There are many creek crossings on the route so expect wet feet. A few can be difficult at high water especially earlier in the summer. Be prepared to encounter bears.
For full details see the Parks Canada route description. Note that their total distance seems to be high and some of the on-trail distance markers can be off.
https://www.pc.gc.ca/en/pn-np/yt/kluane/activ/randonnee-hiking/cottonwood
