I completed this loop solo unsupported in a clockwise direction S/F at Mill Creek TH following the route established by creator Ashly Winchester. There was an active fire nearby to the SE but across the highway. As with many places in Cali now, the smoke was thick and had a strong negative effect on my breathing. I live and train at 6500-8000 ft and recently raced at 10,000 feet with no perceived effect of altitude. Today, my breathing was labored and the 6500 ft elevation felt like 12,000. I wasn't able to run hills I normally can. And I burned a few minutes splashing around in the little creek crossings. I was much more fatigued than I should have been in just a sub 4 hour effort. These are fast and beautiful trails with some amazing lakes down below. I'd love to return and explore and camp at the lakes or bring someone with me to share the loop with. Thanks to the OKT setter and creator Ashly.