We're summarizing all men's winter duathlon trips prior to 2017 here:
Doing the Longs Duathlon in winter proved elusive. Bill Briggs put it this way, "I thought about it for many years and always waited for the perfect mild, windless day when I was available. It never happened." The return bike ride, which drops about 4000' in 40 miles, and will certainly be done during a cold winter night, is particularly intimidating. The winter dualthon was finally accomplished for the first time by Justin Simoni on March 12, 2014, in a total time of 19h46m29s. His engaging account of the trip is here, and he recorded Strava tracks of the ride up from Boulder, the climb of Longs, and the ride back down. Impressively, Simoni's trip was entirely solo and unsupported. Simoni repeated the winter duo in March 2015, in about the same time. A few days later, on March 10, 2015, Anton Krupicka did the winter dualthon nearly 11 hours faster, 8h51m (from the stoplight at Broadway and US36, which would be a couple minutes faster than starting at the Bustop).
Krupicka reported:
I did a completely unsupported Longs Peak Duathlon today (March 10, 2016), so still calendar winter. My Stoplight-to-Stoplight (intersection of Broadway and Highway 36) time was 8h51m. Ascending and descending the Cables.
Boulder to Longs TH: 2h56m+8min transition
TH to summit: 2h40m+4min on top
Summit to TH: 1h14m+10min transition
TH to Boulder: 1h39m
Strava GPS track: www.strava.com/activities/513652951
It'll probably go a couple hours faster this summer.