Heading north from the airport, I saw a sign for Wailua Falls which I knew from all of my reading that it is a double waterfall about 175 feet high, which is taller than Niagara Falls. The falls go into a freshwater pool that is supposed to be illegal to hike down to, but people still do it - so we did. Those pictures are on a disposable waterproof camera that hasn't been developed yet, but here are some shots from the top, which is the way 95% of people see it.
The hike to the bottom was slippery and muddy, but we used the ropes left by other hikers to help us get up and down the steep inclines. Luckily there was another couple at the bottom to take a picture of us to prove that we hiked down (on the aforementioned camera).
We kept going north to Princeville which is where our studio rental was. I used http://www.homeaway.com/ to book both of our rentals. We were on the ground level of a small complex next to the St. Regis. The cliff was beautiful and we could hear the ocean crashing into the lava rock at night and in the morning while it was quiet outside. The mountains were visible from the front door of our rental (you can see those once I post more photos online). We had a delightful experience staying where we did, especially because we could cook our own food.