For what you are doing I would allow one hour. So if your ADR is for 8:10 I would be at the BC busstop by 7:10. Needing to wait for a bus, get to MK, walk to the monorail, wait for the monorail, and finally get into O'Hana is hingent upon a lot of things, you may luck out and get a bus right away, you may not. And due to the popularity of O'Hana you don't want to be too late or they could give your ADR to someone else! I really like to take a cab, its so much easier and as someone else said, it would be around $15. And then you would need to only allow about a half hour.