Caches like this are exactly the reason I love Geocaching - a great spot right under your nose that you never would have noticed. Apparently the park is a completely a secret to anyone under the age of 60 as we were by far the youngest people there.
The GPSr got a signal where it counted and we found it quickly. Leaving the cache was a bit treacherous, but we made it! Took a happy face keychain and left something I can't recall.