About a 250 mile round trip with my Super Tenere mounted buddy, me on my Road King. We just kinda got a wild hair and said "to hell with it, let's do this thing". We rode up to the Diablo Lake overlook on the North Cascades Highway (U.S. 20). Per his little ride computer thinga-majiggy, temps averaged around 27 degrees. 17 where we stopped to turn around and snap a few pics. I think that might be about my limit on a motorcycle.
