Hi Christopher,
I actually live in Toronto so you don't need a website, you just need me! Assuming you will be crossing over from Detroit? I can tell you that you won't pass anything spectacular and there are very few "loops" of any decent distance in the southern region. The real good stuff is a few hours north of Toronto. But, if you absolutely need something on that route, you can catch the Start of the Bruce Trail from Niagara falls and hike along until you want to stop (it's something like 700km long). This section is nice but it is really close to the highway/cities so you have to cross some roads and may not get the secluded feeling of some other parks. There are some designated camp areas but it is best to stealth as they are few and far between.
Algonquin park is nice…personally, I never go there as it tends to be busy and it really isn't anything to write home about. I think it's too close to the city so it just gets all the regulars.
If you can search for my trip reports somehow on this site, they are all within a days drive from Toronto so they are options too, but most are not 50-100 km.
And, just so you know, the "La Cloche Silhouette Trail' in 'Killarney Provincial Park' is the best trail within a few hours from Toronto, it is quite beautiful and the park is my favorite. I would recommend this trail to you but it is about 4 hours north of Toronto.
If you have any questions, just let me know. You can ask super specific questions aswell…I've backpacked here my whole life!
