The South Coast track is one that truly takes you beyond the edge of civilisation. The first two days are relativly easy going.
Day 1 to Port Craig is very well formed and basically flat and mud free with a little bit of beach walking. You can stay at the historic old school house at Port Craig which DoC have done up as a serviced hut. (Non trampers may choose to stay at the commercial facility nearby but this needs to be by prior arrangement with the Hump Ridge track operators).
Port Craig itself is well worth a visit in its own right. It was a major industrial settlement with a huge sawmill and an amazing rail system including 4 historic viaducts that even today are considered an engineering marvel. Information on Port Craig here
Day 2 Takes you along the old tramway to the Wairaurahuri river. This track is of easy gradient, very easy to follow although a little muddy underfoot (Ankle deep at worst, not at all like Stewart island mud.) The last Km or so is more like a normal tramping track as it drops down a couple of terraces and across a bit of rather swampy ground.
Along the way you will cross over the 4 wooden viaducts, including the recently repaired Percy Burn viaduct. While you are there, the track below it gives you a great perspective of how big theses things really are. You will also pass the cache.
Once you have the cache you can either continue onto the Wairaurahuri and take a great ride up the river with one of the commercial jetboat operators (must be pre booked), return the way you came or continue along the South coast to the Waitutu and Big rivers, but those tracks are somewhat more challenging.
For the true adventurer you can continue all the way along to Puysegur point and Preservation inlet, but this becomes a very serious undertaking requiring a considerable degree of planning, preparation and research and is achievable only by the hardy few.
South Coast track info here
There is also a link on this site to the Hump Ridge track operation..
Note: While the Hump ridge track goes over part of this area, only their lodges are private and the track itself and the DoC huts are open to all. There is a ban on camping within 500m of the Hump ridge track proper. (but not the South Coast track)