Take the Scout Trail - it has intermittent blue blazes - to the corner of the park. Waypoint coordinates for the "official" trailhead on the park trail map are given, but for a shorter walk you can just use the steps at the parking coordinates. The trail at the bottom of the steps connects you to the Yulee Trail. Take a right at the intersection and as you walk, keep an eye left and you'll see the Scout Trail running almost parallel to the Yulee Trail; then just make the short bushwhack over to it. It's about 1/4 mile to the cache.
This is a bison tube but I don't think it should be too hard to find. If all is well, you'll know when you are getting close. There aren't usually many humans back here but there are lots of deer, so don't be surprised. Have fun!