If you can handle all of your luggage, then yes, you can debark the ship, clear customs, then go to your transportation. However, the bus may wait until it is full before it leaves, which can sometimes be over an hour from what I've read.
Regular debarkation is done a little differently now, if you choose to do this option. They will give you a luggage tag with a number on it, and you will meet in a specific lounge. An example, I was on the Enchantment back in October, and I had a green tag with the number 8 on it. At guest relations, they will have departure info, which will also be delivered to your stateroom. This will have all the numbers and luggage tag meeting points on there, as well as the time that you will be led to the gangway.
Once your departure time comes, they will lead you down (or up) to the gangway, and you will debark and clear customs, and claim your bag. You will go to the same area that your debarkation luggage tag has, either by color and / or number.
One thing though. For your departure time, announcements are ONLY MADE in the lounge designated for your departure time. An example, my meeting spot on my last cruise was the Spotlight Lounge, and the departure time was 8:30 am. At around 8:15, I went to that lounge, and at 8:30, we were led to the gangway to debark, clear customs, and get bags. Bags are only available in the terminal after your number has been called.
2007 - Majesty of the Seas (Bahamas)
2009 - Enchantment of the Seas (Western Caribbean)
2010 - Freedom of the Seas (Western Caribbean)
2013 - Golden Princess (Alaska, roundtrip from Seattle)