Billy Simpson did the (probably) first ever double SCAR Sept. 22-26, 2014. Simpson's total time was 3d7h25m, taking about 36h for the first "lap" of the route. He reported briefly as follows:
"Totally unsupported fast pack. Carried everything from the start, no drops. Got water from springs along the trail. Started at Fantana Dam entrance to GSMNP at 5:30am on Monday the 22nd of Sept. and hiked to Newfound Gap at 40.3 miles, arriving at 10pm. Slept in alcove by bathrooms. Began hiking at 5:45am Tuesday and hit the turn at Davenport Gap at 5:30pm, made the turn and hiked back to Cosby Knob shelter arriving at 8:30 for a total of 39.1 for the day. Began hiking Wednesday at 5:30am feeling fresh and strong. Hit the road crossing at Newfound Gap at 2:30pm, Clingman's Dome at 5:15 hiking strong and feeling great. At that point I made the decision to hike thru the night to the finish and try to go under 3 days. After hiking for approx 20 minutes after nightfall my brand new batteries began to die only about 1/3 into their expected life for the light. Bad batteries? My brain fart? Who knows? So I switched to the dimmest setting and hiked on to Derrick Knob shelter where I put in my spare batteries. They were not new batteries. I never expected to need them. I decided to keep hiking on dim setting until they died and just stop there and wait for daylight. My lamp quickly faded and I found myself on Rocky Top with too little light to continue for a total of 46.4 miles for the day at 10:45pm. I threw my pad and sleeping bag under a rhododendron thicket and rested until first light. Began hiking again at about 6:45am and was treated to the most spectacular sunrise of the trip. (must be why my batteries died, right!) Hiked in the remaining 17.2 and arrived back at Fontana at 12:45pm."