Auto works very well for the newbie. I tell my wife to "just set it to the green".
That said, you can get a lot more from a bit of knowledge. I often like to shoot without flash, since (a) it's disturbing and (b) the built-in flash has no effect whatsoever beyond about 8 feet, which means if you're shooting a show you'll get an overexposed foreground (probably the heads of the people in front of you) and an underexposed background (the show). So switch to "P", use the "Func" switch to set ISO 400, and turn off the flash. Don't forget to return to ISO 50 afterwards. If you're shooting indoors, also set the white balance to incandescent (again, don't forget to put it back later).
Another problem in Hawaii is going to be shadows: the sun makes for sharp contrasts. Go to P mode and turn on the fill flash (press the lightning bolt until the display shows just the bolt without an "A"). If possible, shoot the picture both with and without fill flash because sometime the flash makes it look bad.
As a beginner, use Stitch Assist mode to help with panoramas. Rather than rotating your body, try to rotate the camera around the rear center of the lens. That'll help the panorama software later.
Finally, when you get there go into a drugstore and buy a disposable underwater camera. It's not a G but I promise you won't regret it.