This itinerary will takes you through a nice wild valley down to La Balme, a small village near La Thuile. This descent is better in spring conditions because then the flat section will be cross-able without any effort.
From the top of Arp station go rightwards to almost reach the Youla Col then head left and ski down the big open Youla valley. The middle section is quite flat and sometimes poling is required (keeping leftwards in this part is better). At the end of the valley, cross the stream rightwards to reach the woods. After a narrow passage ski down and find the path/road back to the summer pastures. According to snow conditions you can ski down this road or the open field down to La Balme village (1300 metres). Get back to Courmayeur using local buses or by taxi. The last part of this run can lack often of snow in spring time due to its low altitude. This run is not suggested for snowboarders because of the flat section in the middle.