What he said. There are bikeable sections of the trail where the trail starts down closed-off roads so you can quickly get into walkable sections without trying to bike over the walking trails. You can presumably hike you bike in also. I have biked over parts of the trail in the good old days before signage. A lot of the trail is on private agri, etc... land so you are often tresspassing in the legal sense if you camp, though how else are you supposed to through hike it. I stay away form the main weekends, and have never had a problem getting a campsite at a provincial camp, that's one advantage of the high costs, and low service level for the sites-who wants them. Marginally off-season often finds provincial sites unattended, or closed. It's too bad the emphasis has moved to long term trailer camping cattagers, but without that they probably would have sold the stuff off already. You main alternative is stealth camping which is possible almost anywhere in Southern Ontario.

I have stayed at KOA, not in Ontario, and been better satisfied, it's usually quieter, and it's expensive, but you get the usual campground stuff like showers, normally better maintained. I have never been turned away with a tent from a KOA including ones in sub-urban big cities, so unless it's A major holliday you probably don't need to book.

It's easy to think of camping in wilderness areas, and I can easily dream up places to camp in my own area, ravines, bush lots, etc... where I would never be seen. It's a little harder to figure out where to camp in other people's back yards. Geocashing sites can point to areas where people seem to feel a sense of entitlement for areas you might consider visiting. i don't have google earth, but surely it could allow you to scope out abandoned areas that are close to areas you want to stop at. Look for places adjascent to a campsite you may not get into, or look at older golf courses and then look for areas that connect by ravine of river back to a parallel road. However, the real sites you find can be a lot smaller than that. It's really not necesary to work at it, but if you like to know in advance where you are staying that's an option. Fishing site maps, abandoned miltary (lots along the waterfront).

Oh, another thing. My actual experience with motels is that they still cost a lot more than even paid camping. I always figure they should be cheap based on, the fact that up till 20 years ago there were places, one or two outstanding, that offered rooms for as little as 10-15 bucks. The last 20 dollar place I stayed at was full of roaches, and my notes show 50-60 is more average. A lot of those motor hotels were built in the 50s and 60s, and have since been sold to people who finally raised the rates, but certainly haven't renovated them to the standard that makes them nice. If I go back to when the motels averaged 20, the campsites were 10.