Warning: According to recent logs, there is poison ivy surrounding GZ so please be careful!
Harvest Hills is a new development that features parks (Harvest Hills park is awesome), Phoebe Gilman Public School (Opened in September 2013) and a future Catholic high school (TBD) and best of all, home to this new cache!
Where the cache is located is known as, "Peggy's Wood." The Regional Municipality of York and Towns of Newmarket and East Gwillimbury are in the preliminary stages of designing a trail system in the area that will connect to Newmarket's trail system.
Parking is available at either the retail shopping centre (where Costco, Superstore etc. is) and is 15minute or so walk to the trail entrance. Dedicated on-street parking is available at Harvest Hills park, or on-street parking is available near the trail entrance (keep in mind, try not scare the muggles who may live near by).
Once you've established parking, follow the trail along the storm water management pond to a steep hill. Climb down the hill and and after a bit of bushwhacking, the cache will be found in crux of a tree and is a peanut butter container big enough for tradeables.
Enjoy!
Congratulations to River_runr for FTF