Derek, in BC the trailer has to have its own plates and collision & liability insurance even though while connected to the tow vehicle it is covered by it as well. Having separate insurance for the trailer although Ontario may not require it, it may be a good idea - if it where to meet with a problem when stored at your home or at a campground for example, you might want to check that your home insurance will cover it - my house insurance does not cover cars or trailers lost due to fire, theft etc. so it needs it owns insurance in that regard as well.
As far as the issue of the value of the trailer goes this was discussed in another thread a short time ago. The thread is here