Please note that the industrial archaeological landscape around Haytor is protected, with the tramway itself being a Scheduled Ancient Monument (SAM). The area around the granite outcrop of Haytor itself is also an SSSI for geological reasons. It is illegal to wilfully damage the area in any way so please be respectful of this wonderful heritage and geological asset.
Haytor, or Haytor Rocks, is probably the tor that sees the most footfall per year. It may not be remote or as impressive as some of the other tors but it is easily accessible, with plenty of nearby parking, and some beautiful views off the moor. As well as this area being ideally suited for tourists to come and get a little taster of Dartmoor, there is also plenty for the more seasoned Dartmoor explorer. The tor has a few notably features, including a rock cut basin, natural in origin, and more than one incident of graffiti. Now whilst that is frowned upon today, and even illegal, the fact that the date says 'JS 1827' (if that date is real) makes it a point of interest today.
In the wider context, Haytor also sits in a fascinating landscape, especially if you know what to look for. There is the feint remnants of a prehistoric landscape, which is seen across much of the Moor. More impressively/uniquely, and much easier for most to identify, is the impressive granite tramway, which serviced the nearby granite quarries, taking the stone down to Teignmouth, and then the sea.
This cache is hidden a short distance from the main outcrop of Haytor, but will still be busy on most days of the year. To reduce any searching time, and therefore the chance of being spotted, I had attached a spoiler photo and a pretty specific hint.