This is the long couloir that ends at the notch. There are several variations that could be a lot harder. The route we took had about 50 feet of WI3 in a chimney about mid-route. The exposure is awesome, and the room for more mixed lines in this area is there. For decending, we downclimbed the entire route I would not recommend climbing it if you're not comfortable descending this way. The only other option is to get dropped off on the west side and carry your gear over and descend the Navajo snowfield. Either way, it's a long journey.
The route starts in Wheeler Basin and follows the path of least resistance to the notch. In the spring, it is obvious from Caribou Pass (see pic). We started at Junco Lake trailhead and left from Monarch Lake trailhead. I would recommend starting at Monarch and taking Arapahoe Pass trail to Wheeler Basin and out the same way.
Some people might want to belay the ice section, but this can be avoided by going left onto a scree slope. Rock gear should be carried if the route is linked to the north ridge. For the route, I used two axes from about a third of the way up to the top.
Looking down the upper couloir.
Entering Wheeler Basin.
North Arapahoe from the route.
About halfway up the route.
The complicated west face of Navajo.