Your best bet would be to take a cab, it's the only way you will be in control of when you will get there. I would have the cab drop me at the entrance to the CR. From there it is a short walk to the MK entrance, and will avoid you having to wait for a monorail or boat from the TTC. The trip is a little less than 5 miles so I would estimate a cab fare of $12-$15 plus tip and at most 10 minute cab ride plus a 5-10 walk to the MK entrance.
One last thing there will probably be cabs already waiting at the valet stand, if not they will get you one quick, and you won't have to walk down to the bus stop and sit there waiting in the dark.