My husband and I took our two oldest children (ages 8 and 9), and I must say the highlight of the trip for them was the hours we spent at the Embassy Suites' pool and at the beaches. They were as brown as coconuts before we left!
Speaking of coconuts, one day I was on my way back to our suite when I saw two of the hotel groundskeepers eating a fresh one that they had just knocked out of the tree. They gladly shared with me. I was amazed at how mellow it tasted. . . and the texture was almost like custard! After that, I tried every tropical fruit I could! The papaya salsa on my eggs in the morning was mindblowing! Oh, and the fresh fish at the restaurants was incredible. I'm not much of a fish eater, but wow!
A memorable moment was driving down the highway in a red convertible with the top down. What an awesome experience to feel the ocean breezes and to smell the tropical air while driving past rows of coffee plantations while listening to the Beach Boys, only to be doused by a sudden warm rain, and to not even care!
Quick Tips:
We found the best opportunity by accident. We couldn't find the Fern Grotto because we didn't realize that the only way to get there was by boat. By the time we finally figured it out, the canoe rental companies wouldn't rent to us because it was after 2pm. One of the workers told us about a tourist"village" along the river on hwy 580 that was on the way there. By the time we started out, everyone else was heading back. We missed all the tour groups at Wailua Falls, and by the time we got to the Fern Grotto, we were the only ones there! It was one of the best parts of the trip.
If you want to do extra "touristy" stuff, like the helicopter tours, horseback tours, scuba boat expeditions, etc., be sure to bring a lot of money, because those things cost well over /person. There are still plenty of things to do on a shoestring budget, though. You can rent snorkel gear for /week at Snorkel Bob's, then any beach can be your snorkeling destination, and there are plenty! I even found three sea turtles on one "guide-less" trip!
Best Way To Get Around:
Definitely rent a car! There are only about 8 highways on the whole island, the two main ones, and then 5-6 "feeder" routes. You just about can't get lost, and even if you do, the people are very friendly, and there's always something else to see or do. You may find a hidden (to the tourists, anyway) delight! Don't worry about missing anything -- the speed limit is 40mph, and there are plenty of places to turn off and gawk at the view (you will).