From the upper Caples Valley, Kay Creek runs NNW up into the Humboldt Mountains. The creek itself is mostly bouldery, with a couple of shingle flats. It is a beautiful stream, full of charm, and there are delightful views up and down the valley.
After cutting the corner from the Fraser Creek turnoff the route heads up the true right of the valley. The first 100m of altitude is gained quickly but thereafter the ascent is gradual. The track itself is well marked but hasn't been cleared for a while so there is a bit of windfall and debris to contend with. After crossing the initial shoulder from the Caples the track stays pretty close to Kay Creek for the rest of the way. Part way along the main clearing a large, active slip comes down to the creek and the path becomes indistinct. In low flows it is possible to skirt around the slip at water's edge. Cairns and track markers show the way up the rest of the clearing, and there are numerous little streams to be forded on the shingle flats. As Death Valley nears the track heads uphill on the true left of Kay Creek - a sure sign the hut is not far away. With the hut in sight there is one final crossing of Kay Creek to be done. The ford is in a steep and bouldery spot which could be dicey if the stream is up*.
Kay Creek Hut is an old, dirt-floored four bunk hut. It was given a spruce up in 2016 by the Otago University P.E. department and now looks quite cosy. Judging by the hut book it is seldom visited (except by the uni groups), with most parties either hunting or heading over into Scott Creek and the Routeburn Road (or reverse).
It took me 2:40 hours to cover the 6km from Upper Caples Hut with a light day pack and no breaks. I thoroughly enjoyed the rough state of the track - it was nice to have a sense of wilderness after the wide easy path along the Caples. Kay Creek would have to be my favourite excursion of the summer so far!
* According to a note in the hut book, if water levels are high it is safer to cross Death Valley stream by the hut, instead of Kay Creek, and continue down the true right until the track is picked up.