Mahon Park is such a great little natural area in the middle of the city. Great trails for walking the dog or just enjoying an afternoon stroll through the forest. North Vancouver has a great website that tells you about all the parks here (and there's a lot), complete with trail maps here.
The cache is a small camo lock & lock hidden on a side trail just off the main path. We did our best to average out the coordinates here but the GPS was still a little jumpy, so we left a REALLY good hint in case you have troubles.
Hope you enjoy!