I've never been to Hawaii so I can't advise you about shooting there.

In general, I would not bring a lot of gear. On most trips with my wife, I bring a 35mm SLR and a couple lenses (wide, normal, and a tele if I think I'll need it), and she brings one 35mm SLR and a standard zoom. We also pack one 35mm point and shoot, usually an Olympus Stylus 100. We're both into photography so there's no argument about bringing cameras, but we agree on not bringing a ton of stuff. I buy film at my destination if possible. One time we went to the beach and I brought practically everything, Mamiya RB67, several Nikons (digital and film), all the lenses I owned, the works. Almost all of it stayed in the bags the whole week, taking up space in our tiny B&B room. I ended up shooting one roll with the RB67 and a few with the F100. After that experience, I've tried to keep the gear to a minimum.

One more thing - I do pack a light tripod whenever I travel.