This cache is located on the trail to the Eternal Spring Shrine.
The Eternal Spring Shrine is a memorial for the 226 men killed in the construction of the 192 km long Central Cross Island Highway, a road that traverses east over the mountains all the way from Taroko to Dongshi.
Start your quest at the parking lot. Cross the big red (Changchun) bridge and go down the staircase on the other side. The trail starts at the tunnel opening on the far side of the area at the bottom of the stairs.
Take the main trail/tunnel less than half the way up to the shrine. The cache is located somewhere in stretch of trail shown in the spoiler pic. The cache container is easily reachable from the path; no need to climb up the rock face or over the railing.
Spoiler Pic
Feel free to post pics of the log sheet but please do not post pics of the cache container.