Take the MK bus and then the monorail to Polynesian. Or you can take the boat from MK to Polynesian. The buses to MK start running very early, around 6:30 or so. They will take you right to MK. But some have mentioned that sometimes a bus driver will drop you at the CR or the Polynesian if he has time, so it doesn't hurt to mention that you are heading to Kona and what does he/she think the best way to get there is.