Here's the info from Ontario on trailers.
The only problem you might run into is the new 'Used Vehicle Information Package' that must be supplied by the previous owner. If they didn't do that they can not legally sell a used vehicle in Ontario.
That and the bill of sale will get the trailer registered. The nice thing is that trailers are a one time registration
fee not an annual like a motorized vehicle.
Oh, and you want insurance on it, you might skip collision if you want but to tow it on the road, liability insurance is a must.
If you're going to be parking it, say for the winter, you can have 'storage' insurance put on it during the off-season. Just don't forget to put full insurance back on it before you go for a spring camping trip.