Full details of the archaeology trail can be found here- https://www.walkhighlands.co.uk/torridon/sand-river.shtml
The marked trail guides the walker around 9 marked features. It is not necessary to complete the whole trail to find the cache, as it has been placed close to feature 4. There are no details at the features so it is best to download them beforehand to better understand what you are looking at.
The walk to the cache site is all uphill and may be wet in places. Good walking footwear is recommended. After the cache site, the path flattens off before continuing downhill.
On reaching the last feature (9) a new track has been constructed which makes the return walk a lot quicker and easier. It does not go all the way back to the start so watch out for the trail markers, in order to return to the beginning of the trail.