The National Three Peaks Challenge involves climbing the three highest peaks of Scotland, England and Wales. Usually, people drive between the trailheads. Cycling or running between the trailheads are other options. Which ever way you choose, the time starts at the first trailhead and ends at the trailhead after the final peak. The total distance is around 450 miles, with the total TH-TH distance on the 3 peaks being about 23 miles with 10,000 feet of elevation gain.
Various records are kept here: https://www.threepeakschallenge.net/three-peaks-challenge-records/
In 1979 Ann Sayer completed the Challenge in 7 days and 31 minutes (female and overall FKT), as stated in her recent obituary https://www.google.com/amp/s/lancswalkingclub.com/2020/04/22/rip-ann-sayer-long-distance-walker-supreme-and-the-first-pioneering-female-centurion/amp/