Reasonable campspots exist on small bush flats between the forks. There are none heading down the Pakuratahi until the last 3km to the confluence with the Summit stream.
For the first 3km downriver, the river is small and frequently becomes tight and choked - but the valleysides are gentle and open enough to scramble along, and in places even walk! This section was about a 50:50 mix of riverbed walking and valleyside scrambles.
Below the major forks 3km downriver from the headwater, the valleysides become steep but the riverbed opens up enough that travel is almost exclusively on the riverbed., Tight gorges are frequent, often blocked by logjams 5-10m tall. Some pools required scrambles on rocksy faces, and a few waist deep required wading, but the river was small and slow and in normal flows was navigable. This section would be impassible in high flows though. Going is very slow, I averaged 1.5km / hour, rather than my normal 2-3 for riverbeds.
Eventually the tight gorges open out and the logjams disappear completely.The river gorws to moderate size, but crossing are still generally knee-to-waist deep in normal flows, and slow flowing, Travel was for the most part on the stony riverbed with a few scrambles in thick fern & windfall vegetation on the banks for a few short pools & gorges. For the last 3km, campspots were frequent.
The only gorge requiring a swim was 300m above the confluence with the stream draining from the railtrail summit. This was 50m long and very deep, but could easily have been bypassed ont he true right.
To reach the railtrial, I;d head about 100m up the Summit sidestream and find a good place to climb the bank to the railtrail. Vegetation near the forks is thick and gorsey, and too far up and the railtrail enters deep cuttings, so try around the 100m mark.
Summit campsite / picnic area is 1km further up the railtrail.
Note: Described in the reverse direction to your journey
The only access to the Pakuratahi that I could find was about 100m up the summit sidestream from the confluence - just downhill from a small cutting on the railtrail. A steep scramble through scrub and grassy slopes led to the small stream draining from Summit. A simple 100m walk down the flat riverbed / valley floor followed to the confluence.
The Pahuratahi is quite large and confined by steep valleysides and gorges for most of it's length upstream. The only spot I hit really deep pools (swimming required) was in the first gorge 300m upriver from the confluence. As such, I;d advise staying on the eastern bank and climbing over a small knob before returning to the river above the 1st gorge - at least I wish that's what I'd done!
Above that, the river is generally knee-to-waist deep in normal flows, and slow flowing, It would be impassible after heavy rain. Travel was for the most part on the stony riverbed with a few scrambles in thick fern & windfall vegetation on the banks for a few short pools & gorges. For the 1st 3km, campspots were frequent, but above that there was almost nothing flat enough, clear enough and big enough to pitch a tent until the headwaters.
As you head upriver, tight gorges become frequent, often blocked by logjams 5-10m tall become frequent. Above each is a flat expanse of gravel and easy going until you get into the next gorge, I remained almost continuously in the riverbed until the last main forks 3km below the headwaters. Going is very slow, I averaged 1.5km / hour, rather than my normal 2-3 for riverbeds.
From the last forks the river frequently becomes tight and choked - but the valleysides are now gentle and open enough to scramble along, and in places even walk! This section was about a 50:50 mix of riverbed walking and valleyside scrambles.
If you're watching your map, the point to leave the rver at the last forks and climb the ridge to the pass into the Waiorongomai is obvious - the now very small stream forking SW / SE.
Reasonable campspots exist on small bush flats between the forks. There are none heading down the Waiorongomai until pretty much the hut,.