Stuke Sowle submitted the route:
This route traverses the southern portion of North Cascades National Park. I find it very similar to the Rim to Rim route of Grand Canyon National Park only it is from Pass to Pass.
The route gives the traveler a glimpse of what the park has to offer with rugged peaks, deep valleys, and alpine meadows along the journey. The route starts at Rainy Pass along Highway 20 at the Rainy Pass Picnic Sign along the road, you will find the PCT. Head south on this trail for approximately 14 miles to the junction with the Upper Stehekin Valley Road. Follow this abandoned road west until it becomes the Cascade Pass Trail at Cottonwood campground. Continue on the Cascade Pass Trail as it climbs it's way to Cascade Pass. The stone benches at Cascade Pass mark the completion of the route unless you are doing the out-and-back, or Pass to Pass to Pass.
I believe that the route can be traveled in either direction but take note that there is a 3.3 mile with 2,000' of gain approach to Cascade Pass if coming from that direction. This is not part of the route so if you are traveling eastbound on the route, the clock starts once you are at the stone benches at Cascade Pass.
One way the route is approximately 26 miles with 4,500 feet of gain (5,000' of gain if going from Cascade Pass to Rainy Pass).
[Note: This route is in the southern North Cascades, while the North Cascades Traverse route is in the northern North Cascades!]