Normal
You may get an upgrade when you book a category guarentee. This means you will get what you paid for or better. If you request a certain cabin perhaps because you want to be mid-ship you will not be upgraded because the cruise line assumes you want that cabin. Many hotels will allow you to park your car on their lot and will shuttle you to the ship. I don't know specifically about New Orleans. Someone on the board did that for about $85 and the parking alone would have been $70. I don't know if it was in New Orleans. For a 1:00 embarkation many people say in their reviews that they arrived at 11:00. Since you want a specific date you should book now. Some people book over a year ahead. If the price goes down before final payment you should have no trouble getting an adjustment. After final payment you may get a refund, ship board credit or upgrade. You'll have to ask. You won't automatically receive anything. Although I may have read on here about agents who will track the price for you.