I think that a lot of people begin flying in around 11, noon or after and that is when you get the lines (especially more around 2-4 in the evening) as some people go directly to the parks without pre-checking in and then come back when they think the room is ready. The last couple of vacations I've had there, I've checked in between 8-11 a.m. and only had to wait a couple of minutes each time (10 minutes or less most of the time).