You can access the limestone-gravel path from both Lions Park and Lone Oak Park, but access is at the very back of each, along the railroad, and neither is well marked. The easiest way to access the wooded path is from the paved foot-and-bike path that runs alongside Valley Rd. The woods are pretty, but I wouldn't recommend swimming in the muddy pond.
You're looking for a bison tube, wrapped in camo tape. You'll probably find some stray baseballs, too. We returned ours to the park's batting cage, but consider any you find a bonus.
Please take care to replace the cache in the same manner you found it to protect against the elements and muggles.