This is intended to be a fairly simple hide in a fairly obvious place in the Northfield Memorial Park. It was hidden in the greenery to help keep it out of any muggle view. BYOP
We learned from x_0 and 99celing that there is an honest-to-goodness letterbox very near this cache. This cache is a preform, not a lock 'n' lock.
Congratulations to Snarfmon23 and BrownDog09 (those FTF hounds 
) for being FTF!