The Sign of the Packhorse is a classic Canterbury day trip or an overnighter in a historic hut.
This is a bit of a grunt and should be done with due regard to the weather and track conditions. Wear sound footware take warm and windproof clothing, as well as a bit to eat and drink.
There are about 4 tracks that lead here and several different access points
For the fit and fast this could be tidied up in less than 2 hours, but to enjoy the area you should allow a lot more
I have placed an old marmite jar in a spot not visible from the hut, but you could get muggled by someone approaching from Gebbies, however it will be easy to make like you are just exploring.
If you are thinking of staying the night it is not a simple as just showing up anymore, have a look at the this http://www.doc.govt.nz/Documents/parks-and-recreation/places-to-visit/canterbury/mahaanui/te-ara-pataka-brochure.pdf it gives a pretty comprehensive explaination of what to do