The earliest PAT is 11:00. Yes, a silver CC member can get that. Also, if you are using
DCL transportation, you don't care what your PAT is--you'll get in as soon as you get to the terminal. If you are coming from MCO, you'll check in there including getting your boarding card.
On the classic ships, the terminal is not at all a mess at 11. The terminal can more than handle that volume, and the PAT system has eliminated a lot of the "gotta be there first" mania. Remember that only a small percentage of guests on most cruises are Dis-ers....the others don't know why they might want to show up early!
The silly stuff--people who crowd around the entry area. You aren't going to get in any earlier or later by crowding that space. As above, have a seat, see characters, look at the model, use the restroom, and just chill out for a bit. When the number ahead of you is called, you can start to move toward the entrance. If you are number 27 and they are on number 3, GO AWAY and relax.
Boarding goes very quickly once it starts so people start moving rapidly onto the ship.
On the bigger ships, the Dream tends to be more crazy than the Fantasy. But still, not a problem at all. The system does a decent job of spreading out the arrivals.