The new bike path around the back side of USAG Humphreys (K-6) was recently finished and I felt there should really be some caches along it. Unfortunately, local reviewers have enacted some policies regarding caches around military posts and wouldn't publish most of the caches we placed; of the 17 caches we put out, the reviewer only published three at the very end of the trail. On the positive side, these caches are the ones closest to the cafe the trail leads to so you can still enjoy a cup of coffee and the view.
Keep in mind that the distance from the current beginning of the trail to the current end of the trail is 10 km (6.2 miles), if you don't have someone to meet you on the far end you can expect to bike at least 20 km. round trip. If you choose to walk the trail you can take the 16 bus from Pyeongtaek Station/AK Plaza to very near the first cache and catch the 15/15-2 bus back from right in front of the "T House." Depending on the time of year insect repellent is a must when hiking/biking this trail.