Do keep in mind that people on this board are a little nuts and anxious (I mean that in the best way). The doors open around 11:45 - maybe (depending on how debarkation and turning over the boat goes) as late as 12:15 or 12:30. To be the first people (or the first twenty), you'll need to be there when the terminal opens and camp in line. But Palo seats more than 20 people and not everyone wants the same spa treatment at the same time. When we cruised, by 11:30, the line snakes back through the terminal, and there are probably several hundred people in line....When the line starts moving, it took about twenty minutes to get back to the ropes, another ten and you could stroll on.
Out of the 2000 guest on board, maybe 300 will board in that first half hour. Of those, not everyone will be running off to get Palo or spa ressies.