There is no direct bus to the MK.
No sorry, you cannot walk to the MK.
The boat takes 10 minutes or less, and is a nice ride.
If you drive, you will have to park in the main lot, then either ride the monorail or take the ferry from the TTC to the MK, which would take you the better part of 20- 30 minutes.
Really, your best bet is the boat!