We took the bus to the port from MCO and it arrived at approximately 11:00 - 11:15. It was not the first bus from the airport but pretty close to it. There were very short lines to check in, just walked right up to the counter. Check in didn't take more than 15 minutes and got in line which had approximately 50 persons ahead. CM's started letting people board at about 12:15-12:30. From start of boarding till we got to the door took no more than 5-10 minutes.
So no need to rush.
We went to our rooms first ( deck 8) dropped our carry-ons then to beach blanket for lunch, DD went to Oceanears after lunch for DGS check in and I went to Route66 for Palos ressie. They divide you up into days you want to place a ressie for and then by number. I was number 8 in line for Wed evening on a 4 day cruise and got the time I requested which was for 8 pm.
I hope this helps.
KennyK