This charming little park is located not far from my base of operations. I first noticed it while driving past and just recently took a walk to check it out. It's east-west orientation runs oddly perpendicular to most other walkways in the area, and the fact that it is so much shorter than the others it makes me wonder "What were they thinking?" when they added it into the layout of this neighbourhood.
I thought it could make for an interesting spot to place a quick short multicache, but I wanted to elevate it above the typical PNG cache (that's Park-N-Grab for all the muggles and noobs reading this) so I have placed a deliciously diabolical cache container to confound you, just to make it interesting and justify the D4.5 rating. And remember, a good cacher always carries a writing implement! 
I hope you enjoy this little diversion! And yes, it plays very much like a letterbox.
As you are probably aware, the posted coordinates are not where you will find this cache, but they are a good starting point. Please keep in mind that you are in a residential neighbourhood so drivers be careful where you park. Don't block driveways or fire hydrants, and avoid front lawns. When you reach the coordinates you should see a round metal object in the ground. Read the first word on the object and remember the final letter of that word.
If you are observant, you will have noticed there are some postal boxes at this end of the park. Now you need to locate another set of postal boxes by using that letter from the first round object as your compass heading from the posted coordinates. When you arrive at the second set of postal boxes you should be able to see a pair of round metal objects in the ground surrounded by concrete. Position yourself beside the southmost round object with your back to the postal boxes. Look for a red item.
Using this red item as "The Sun", answer this question to obtain your hint for finding the cache: What is another colloquial name for our planet that references its postion in our solar system? (Hint within a hint: the answer was also the name of a popular TV sitcom that ran on NBC from 1996 to 2001). Use the hint and look low.