Like DTW, I'm always anxious to get aboard, and we usually arrive at the terminal around noon. Being Platinum on Carnival helps a lot, and we normally are aboard by 12:30 at the latest. The WORST situation I've encountered is at Port Canaveral, and it's the LUGGAGE DROP OFF! I don't understand it, but for some reason they just can't get their ducks in a row! I've waited in line, in the car for up to an hour, just to drop off the checked luggage, and the answer, before you ask is, NO once you're in line, you can't get out. This has happened twice over there, so in the future I very carefully look at the area and see if I can determine whether there is the usual big back up, and if there's any doubt, I simply park, and roll my checked luggage to the terminal.
Easiest embarkation we've experienced, is without a doubt, Tampa. Quick, painless, and very, very friendly.