There is actually 1 race track that is really close(Dunnville Autodrome). And another course that is about 40min east(Toronto Motorsports park)
I've emailed the Dunnville Autodrome about availability and pricing for later this year and next. I'm going to do the same for Toronto Motorsports park.
Seriously, this could be a really cool thing to do!
UPDATE:
Toronto Motorsports park ~40min away from Campground
The rentals are from 9am to 5pm.
ALL PRICES IN CDN $ and dont' include 14% tax
Weekend or Holiday
3km - $4600 / 50ppl - $100
1.8km - $3,200 / 50ppl - $65
1.2km - $2,900 / 50 ppl - $60
Weekday
3km - $3,100 / 50 ppl - $65
1.8km - $2,200 / 50ppl - 45
1.2km - $2,000 / 50 - $40
Evenings 2h minimum
3km - *$500/hr = $1000 min / 25 = $40
1.8km - *$300/hr = $600 min / 25 = $25
1.2km - *$300/hr = $600 min / 25 = $25