Some History:
King's Highway 401, commonly referred to as Highway 401 and also known by its official name as the Macdonald–Cartier Freeway or colloquially as the four-oh-one, is a 400-series highway in the Canadian province of Ontario. It stretches 817.9 kilometres (508.2 mi) from Windsor to the Quebec border. The part of Highway 401 that passes through Toronto is the busiest highway in the world, and one of the widest. Together with Quebec Autoroute 20, it forms the road transportation backbone of the Quebec City - Windsor Corridor, along which over half of Canada's population resides. The entire route is maintained by the Ministry of Transportation of Ontario (MTO) and patrolled by the Ontario Provincial Police. The posted speed limit is 100 km/h (62 mph) throughout its length, unless posted otherwise.
On August 24, 2007, the MTO announced that the stretch of Highway 401 between Glen Miller Road in Trenton and the intersection of the Don Valley Parkway and Highway 404 in Toronto would bear the additional name Highway of Heroes (French: Autoroute des héros), in honour of Canadian soldiers who have died, though Highway 401 in its entirety remains designated as the Macdonald–Cartier Freeway. This length of the highway is often travelled by a convoy of vehicles carrying a fallen soldier's body, with his or her family, from CFB Trenton to the coroner's office at the Centre for Forensic Sciences in Toronto.
Wherever life takes you, travelling on the 401 can probably help get you there 
!
The Cache:
BE WARNED!! The area is prone to high muggle traffic! PLEASE use stealth where needed, and keep the cache well hidden!
Finding the Cache:
LETTERBOXING Style:
The posted co-ordinates will take you to the first truck parking stall along the treeline. Travel 18 stalls easterly, where you will discover a lamp post which appears to have been backed into by a truck (it's quite bent )!
Inside the treeline at this location, lies the cache (might be a tight squeeze getting in)
!! You will find the light of this bent lamp post is almost directly over the cache
"MULTI-CACHE-WITH-A-STAMP" Style:
There is a film canister hidden at the posted coordinates with the coordinates of the cache.
Enjoy!
On a side note...
This particular stop along the 401 has off-ramps and on-ramps in BOTH directions. It shouldn't be hard to find your way back onto the 401 and continue on your journey after locating the cache, no matter where you came from or where you are going
You will probably discover that the area around GZ is in some dire need of CITOing! 
Do help where you feel you can!