Originally we planned to follow the trails as it described here, but when we arrived to the park and tried to arrange the campsites at ranger station, most of the campsites have been filled up and we have to change the dates or the route. Because of the campsite availability we had only two campsite areas on the route: South Fork Cascade Creek and Death Canyon. So, we decided to add additional loop to the root and after the Alaskan Basin go through the Death Canyon Shelf, turn and get back to Phelps lake. It added about 10 miles to the route. The tough part was that it extended the distance to hike and shortened the time. We had only three days.
What can I say? We made it. Yes, it was really challenging, but quite exciting. The trail is difficult, there are at least three climbs and descents about 600-800 meters. (multiple by 3 to get feet). We sidestepped to get to the Avalanche Divide, which gives great views. Since it is a side trail, we left our backpacks on the main trail to get there, but it took us about 2-3 hours (round trip), which added to our second most exhausting hike on the trail (we covered about 17 miles that day).
In conclusion I have to say that the trail is difficult, but not impossible, but after that you will be in great shape, exhausted, happy and will never forget the views and emotions you went through. It really worth it. But, take it a bit slower than we did :)