The cache is located left side near the way from Elephants Terrace and Phimeanakas Temple. Enjoy the silence of this green place which is good for a little rest during your temple tour.
You have not to climb on any ancient stone. There is a footpath around the residues of the unnamed small temple which leads you to the cache.
View spoiler picture to help preserve this historic site and prevent any geo-damage.
Small note: There is a local guardian for cache maintenance.
Bring your own pen!