I would love to get into Cooksville Auto Wreckers, in Mississuaga. There are a ton of vehicles, wierdly enough, in the middle of the City. Regretably, they keep it well fenced both physically and visually. I suspect the soil is contaminated enough no one wants to buy them out yet, for the cost of the remediation.
I have heard of a scrap yard out Bowmaville/Kingston way off of the 401 that has cars from the 30's and 40's with forests growing up through them.
Off of 9th line here in west Missisauga there are a few land holdings with good collections of old derelict trucks and farm machinery between Brittania and Derry, that you get a glimpse fo as you zoom north on the 407. I have yet to find the time to see how one might negotiate access. Their buildings that front along 9th Line seem to be going concerns.