Kaipo and Selena are two of the best hosts you could possibly wish for. My wife and I stayed with Kaipo for a month while looking for a long-term apartment after we moved to Hilo. We stayed in the downstairs ohana unit, with its own bathroom, kitchenette, walk-in closet, and living room space. It was perfect for us. Kaipo and Selena were friendly, helpful, and informative, and great people to sit and chat with in the mornings. The house is beautiful, and sitting on the lanai in the mornings and afternoons is a really pleasant way to unwind. I really can't recommend it enough. If you're looking for a quiet place to stay while exploring this side of the island, Kaipo's place is a perfect choice.
About the road: Follow Kaipo's directions, not Google's. The road is fine when dry, and even when wet the only problem is the last corner before the house which tends to flood in heavy rain. When we were there, Kaipo was discussing plans to fix the corner, but until then I'd recommend an SUV unless you're visiting in the dry months. 4-wheel drive isn't necessary, it's more about having a few extra inches of clearance and bigger tires. Our Chevy Equinox rental (2wd) was fine, and it rained a lot during our stay.