The cache is a 1.25 litre plastic container painted camouflage style. It is located within 15 metres of the lookout at the summit of Mount Pirongia.
Allow 3-4 hours each way (from the described start point) for the reasonable tramp to this summit, not for the inexperienced or unfit. Weather here can change quickly, be prepared. There is a DOC hut only 20-30 minutes past the trig if the weather closes, a better choice than going back down (it's only a 6 berth hut though). Included in the access to this cache is the equivalent of minor rock climbing (no gear required, DOC has fitted chains to the rock faces).
The best start point is the end of Corcoran Rd. My description in starts in Te Awamutu, the central roundabout (nearest to McDonalds) there is signposted to Pirongia, then at Pirongia turn right as the large sign indicates (Pirongia Forest Park). Take the first left off this road into Te Pahu Rd. Once on Te Pahu Road ignore the signposting, you do not want to access via the first few forest access's as they take longer. Turn left into Corcoran Rd, it is the fourth road on the left off Te Pahu Rd. You will be passing the Lookout!! Ruapane cache whilst cluimbing to this cache.
DOC has an excellent leaflet "Pirongia Forest Park" which should be available for around a dollar, a good investment, as is the Te Awamutu S15 Topographical Map. Try to pick good weather, the views from Pirongia are awesum and include Ruapehu and Egmont (Taranaki).
The cache is not visible from the tracks at the summit, you will need to go a few metres off the track, however it isn't difficult stuff. The cache is very obvious when looking back towards the track. The GPS fix was from directly above the cache, it should get you to within a metre or two.