Google maps and GPS can often send you astray, especially if you type in my address. However, if you enter "Wheelbarrow Farm" to google maps, that should bring you here.
From Toronto:
Take the DVP/404 north to Davis Drive in Newmarket
East on Davis (25 minutes until it ends at 23/Lakeridge)
23/Lakeridge north for 10 minutes to the flashing yellow light at Durham 13