See
http://www.frugal-rv-travel.com/Ontario-boondocking.html
excerpts per that website
"Even in Ontario, I have managed to find free boondocking locations. As a woman traveling alone, when I started out, I wasn't sure how much I could count on finding Ontario boondocking places that felt safe. I'm amazed myself! Nothing can compare to the campsites we find on our travels through the southern States because, here in Ontario, we don't have as much accessible "public land." However, finding or "creating" a safe boondocking spot for one night at a time turns out to be fairly easy, if you put my mind to it. For me, this worked perfectly on this trip, which was all about exploring a new area for a day or two and then moving on."
"All you have to do is be nice and ask permission. Yep, Ontario boondocking can be that simple. For four full weeks now, I've been traveling through Ontario's "cottage country" - the playgrounds of well-to-do Torontonians. You would think these are not exactly areas where someone passing through in a 20-year-old camper-van might be invited to spend the night, parked for free. Yet, I've done it. I paid for camping four nights out of the past twenty-eight and found free boondocking the rest of the time. When, where, how, and with who's permission? Actually, I find free overnight "parking" almost anytime and anywhere I ask for it.
Sometimes I ask local people who I've had some interaction with. I explain that I pay for camping sometimes but, often, I just want a quiet, safe place to park overnight without getting into trouble for it."
"On my budget, I don't eat out a lot but, twice on this trip, I chose a restaurant for dinner, not only for its menu, but for the level, quiet parking lot in what appeared to be a safe neighborhood. A couple of words with the waitress, who consulted the owner and, both times, I was given permission to stay the night. In fact, one owner suggested, " Why don't you park in the staff parking area....I think it will be quieter.""