The buses to the Magic Kingdom start at 6:30 AM, so if your waiting for them a few minutes before you should make it and when you arrive at the Magic Kingdom use the walkway when going to the Contemporary, since it's located very close to the bus station. Also the bus drivers might ask if you have any ADR's for Chef Mickey's and will dropp you off in front of the Contemporary, however that does not always happen since it's not an official policy the bus drivers must follow.