The cache is located along the pathway at the back of the Athletics oval. This area is an off-leash area, so feel free to bring the geo-dogs. When you get to the trees with the names, you've reached the right spot but the geokids ruled out hiding it up the tree (insert sighs of relief or groans of disappointment here).
There's plenty of nearby parking, unless you come on a Saturday, and during Baseball season parking is at your own risk.
This shouldn't be too difficult to find. Geocache contains log and pencil (and I think some tiny SWAG was added by Remmus) - you may have something that fits but PLEASE ensure the cache closes properly - if it doesn't, please don't leave it....please also take care with the internal positioning of the scribe when closing - it should snap shut with a pinch...hopefully the container will hold up, but I'm not sure how waterproof geoJorjy's choice of container actually is!
oh, and watch your head!!