We sailed the Majesty in April, arrived at the port around 11:15 am and were in a long line already to board. We ended up boarding a bit after noon and our cabins were ready by about 1:30pm, luggage waiting.
I suggest getting on early- although you can't go to your rooms right away, there are plenty places open to eat and you can explore/enjoy the pools, etc.
Majesty OTS, 4/07
Mariner OTS, 4/08
Adventure OTS, 4/09