I don't backpack as much as I used to in my early days in Colorado, but we used to sing Val-da-ree often on the downhill run. (In Colorado you always go uphill to camp and downhill back to the car). Singing while going uphill was always too much effort, especially with a full pack, tent, food, beer, etc. But coming back down the same trail, you adopt that lurching forward marching style, pack creaking, water cup dinging, and singing val-da-ree just seemed to help keep you in your rhythym.
Ah those days of bright sun, rushing streams, the crisp smell of pine, the feeling of your body strong and vital, the mental clarity of high altitude! Val-da ree indeed!