I've never heard of anyone doing this as an out and back hike. Both times I've done it, we've continued on from Twin lakes to Red Rock Canyon and finished there. It makes it around 33-35 km (20-22 miles). The hike is gorgeous with meadows, ridges, and lakes all the way along. The first time on the trail was a 3-day backpacking trip. There were good places to camp at Lone Lake and Twin Lakes before the fires. The second time was as a one day hike and it was one of the best hikes I've ever been on. It was long but doable. Hopefully the trail will open up again soon.