We found the best way for us is to drive our truck to the TTC and take the monorail from there.  It seemed to get us there a little earlier than the boat-CR-monorail route.  That was to get to CP and CRT but it would work well for 1900 too.  I don't know if you are allowed to park at GF if your not a guest there.  That would be the best way if it is allowed and you have a vehicle.