This is a popular spot to hang out on a hot day. There might be people wading in the brook or admiring the series of small waterfalls over slabs of rock. It's a great spot for some photos in the fall or anytime, really.
You will be looking for a hide befitting a place called Stickney. It should be hard to spot. A tool for seeing better in dark places might help. You are looking for a micro-sized container.
There's a spot to park off Route 30 or you can park on Stickney Brook Road, but you'll have to hop the brook from there. You won't have to stand in water to access the cache, unless there has been a big storm?