Note: The sidle from the large basin at the head of Pine Creek to the ridge line overlooking Lochnagar is extremely steep and exposed and almost entirely on snow grass. You have to go through two sets of bluffs. A slip would be serious. Only attempt this crossing in perfect conditions and carry an ice-axe or other means of arresting a fall.
From Lochnegar Hut, follow the lake shore north and cross the lake outflow. Climb the spur on the other side. Going is scrubby at first but once the spur becomes more clear a good ground trail exists. Follow the spur upwards until the left (western) side starts to become bluffy, and then sidle left (west) off the spur, round the base of a brief bluff and into the gully west of the spur. Follow this gully up to the saddle between pt1865 and pt1896. The climb is steep in places, but generally good going with only brief scrambles.
Cross the saddle onto the faces above Pine Creek to the north. Sidle the faces above Pine Creek NW for 200m until going becomes difficult due to bluffs descending from pt1896. Descend approximately 20m down the snow-tussock spur just before (SE of) the tricky bluffy section and sidle into a basin below the bluffs. This is a very steep descent on slippery snow-tussock with exposure to serious falls - take care and use an ice-axe.
Sidle the steep faces above Pine Creek at your current altitude north past pt1896, past the next saddle until a scree terrace appears below you - just before you come level with pt2000. Descend to this terrace early, before impassable bluffs develop below you. This is another steep scramble down.
Follow the screen terrace east of pt2000 and into the basin at the head of Pine Creek. These are broad desolate gravel and ice flats. Once int he basin you can drop to Pine Creek and follow the TR of it north up to the saddle at pt1950.
Beyond pt1950 is the vast Snowy Creek valley. Several spurs appear from the top to be good routes down, but most bluff out at their base, so follow the route described here. Head north from the saddle for 2-300m, crossing a small but steeply incised creek flowing west. Follow the spur to the north of the creek west and down into the Snowy, passing a cairn marking the start of the descent. One set of bluffs at 1800m can be avoided by dropping south of the spur towards the creek, and then sidling back onto the spur once beneath the bluffs. From there it is an easy tussock descent to the Snowy, with amazing views of the hanging glacier opposite the whole way.
Follow the Snowy downstream - the entire descent can be made easily on the southern (TL) bank, though crossings would be easy enough in low flows. Just prior to the Rees Saddle the Snowy enters a gorge. Do not follow it into the gorge - which Moirs says is impassable. Instead, climb the faces to the south to the easternmost saddle of the three visible. Here you will find a small tarn, and the Rees Dart track 50m beyond it.