Distance: 4.8 km (2.8 DOC hours) - Tramping track - Easy-moderate terrain
Altitude: 479m to 649m. Gain: 290m. Loss: 122m . Gradient: 5 deg (Moderate)
Skills: - Occasional rivers (3/6)

Tramping track (4/9)
Cut, marked tramping track: natural, rough ground surface

Primary, mapped (1/5)
Formal route, on maps, principal access to hut or along range / catchment

Moderate (difficulty: 3/5)
Occasional moderate climbs

Easy-moderate (difficulty: 2/5)
Tussock / river-gravel / open bush / cut track

None (difficulty: 1/7)
No alpine skills required

Occasional rivers (difficulty: 3/6)
Occasional rivers - impassible after heavy rain

None (difficulty: 1/7)
No alpine skills required

From Mangahao Flats hut, the track climbs gently up the valley. There is a climb up and over the obvious slip around 540m and several large side streams to cross (these would be difficult/impossible in flood. Several of the flats have good campsites including at the base of Triangle Spur (1 hour 45).
South of the spur, the river divides (2 - 2.5 hours) and after crossing the Mangahao follows the unnamed branch, then crosses and climbs gently up on to Girdlestone Saddle

Note: Described in the reverse direction to your journey

Drop gently down off the saddle to follow the unnamed tributary and join the Mangahao River at the forks. The track then ambles gently down the valley passing some nice flats for camping at the base of Triangle Spur. There are several large side streams that would be tricky in flood.
A large slip is climbed after the base of Triangle Spur and a stream are crossed.