Timed to start runners off just as fall is arriving on the leaves, trees and slopes of these Rocky Mountain ski resort towns just west of Denver, the Golden Leaf Half Marathon takes runners on a point-to-point course that starts in Snowmass Village and finishes in Aspen, for a race that has been lauded by the likes of Colorado Runner and Trail Runner magazines as one of the country’s most scenic trail races.Several hundred runners crossed the finish line every year, a jump up from the previous years when a few hundred finishers completed the 13.1-mile trek across the trails and mountain roads between the starting line on Fanny Hill in Snowmass Village — which lies at an elevation of just over 8,600 feet above sea level — all the way to the finish line at Aspen’s Koch Park, at the intersection of Garmisch Street and West Cooper Avenue.Because it’s run at such a high elevation and because it incorporates a number of technical and challenging trails, the race will definitely challenge most runners who attempts it — especially those who aren’t used to the altitude, which one runner noted caused several participants to struggle with the climbs, especially in the early going. There are also plentiful hazards along the course, with loose rocks and possibly muddy areas, depending on the weather leading up to the event as well as the day of the race.You also get a sense that this is a race for the hardiest of runners when it has been cancelled only once in its more than three-decade-long history, in 2006 for a heavy snowstorm that socked the Aspen and Snowmass area.