The Nadeau Trail follows the west side of Panamint Valley, roughly in a north-south direction between the Argus Range and the valley's paved roads. Measuring a scant 27 miles long - and for the most part completely straight - the casual observer may wonder if allotting three days to travel this road is two-and-a-half days longer than necessary... I can assure you that it is not. Colorful side canyons, historic mine sites, glorious overlooks, and mysterious geological formations easily filled our days to the brim. And the icing on the cake? A hunt for, and ultimately discovery of, petroglyphs -…