The side of the island where Kona is is barren. It is a small part of the island. The rest of the island is far from barren. It has rainforest and the northern part of the island is green rolling hills with spectacular ocean views. The Puna area is a ways from the volcano and lava flows and is a gorgeous area. It also has very affordable real estate. Lots of truck farms in the area and fruit everywhere. Hilo is still a fishing village where you can go pick out which fish you want to eat for the day at the fish market.
Most people have a very skewed view of Hawaii. They think It is all like Waikiki or Kona. Far from it.
BTW, the diagonal highway is nice (SH200)! It is new and we were one of the few cars on it.
Our observation...
The whole west side of the Island was mostly lava fields (except around Kona). The airport is surrounded by rolling lava fields for miles and miles. King Kamehameha's “birth place” (north west) is all lava fields.
The North and East are lush and green. This is contrast to all of Maui was is mostly lush and I imagine Kauai is even more lush than Maui.
It was explained to me that it is because the Big Island is newer and hasn't had the millenia for the forests to fill in and the weather to wear down the rocky lava terrain.
The couple on Buying Hawaii bought a place north of South Point. It was in the high risk lava plane. There wasn't any water or electricity and it was in a very rocky lava field. They paid around $250K for it.