Waipi'o Valley is located at the bottom of 2000 foot cliffs near Honoka'a. You might catch views of 1300 foot waterfalls, wild horses, taro fields, and locals hanging out at the beach.
The view from the lookout is pretty amazing on a nice day, and if you're feeling like a bit of a workout there's a road heading down to the valley floor. This road is paved, but requires four-wheel drive because it's so steep. I hear it's the steepest paved road in the United States, and can be slippery when wet. Walking up was one of the only things that would tire my dog out when she was younger. Most of the time you can also hitch a ride in the back of a truck heading up the hill if you don't want to walk it.
This valley has been used for taro farming for hundreds of years and used to be more populated, but a tsunami came through in the 1940s and destroyed most of it. The folks who live there now are friendly, but please stick to the road and avoid trespassing unless you are invited onto someone's land.
There are also tour groups that will take you down in a van to site see or ride horses around the valley. I did one of the horse tours and it was fun.
At the bottom of the road heading down the valley side, take a right to head to the beach. The sand is a bit course and it can be windy, but it's a pretty area. The waves are usually somewhat rough.
If you cross the Wailoa Stream and walk along the beach to the opposite side of the valley there is a trail that heads out into some other valleys, but this is more of a backpacking trip than a day hike.
If you take a left from the road coming down the hill it will take you farther into Waipi'o Valley where you'll see taro fields and other farms, and a couple waterfalls. There are a couple places where streams run across the road so be prepared to wade.
I recommend bringing bug spray.
When you are done I recommend heading into Honoka'a for some delicious food at Grandma's Kitchen, and just wandering around the downtown area. There are quite a few little shops, restaurants, and a nice little community theater.
We lived for two years down the little wooden alley way right next to Grace Flowers off of the main street.