Check out Volcanoes National Park!

There may be awesome beaches near Kona, but you'd be missing out if you only stayed on that side of the island!  While the west coast can be dry and arid -- almost like California -- the east coast is wet.  The rains come fast and hard, leaving behind a lush, green landscape, a proper tropical jungle.  Hilo is the biggest city on the east coast (and of the island), and while it's a nice town with a few gorgeous parks nearby along a beautiful river, you really can't spend more than half a day there.  Instead, the real attraction is Volcanoes National Park, the sight that makes the Big Island truly unique.  It's located in the south east corner of the island, about 2.5 hours away from Kona, and it contains an actually live volcano constantly oozing lava, dumping it into the ocean and creating new land.

Mel and I spent 1.5 days there last time.  On the first day, we hiked down to the Kailuea Iki Crater, a moderate 4 mile walk through lush trees down to a stunning vista at the crater bottom.

We also checked out the Thurston Lava Tube, which has an unlit section towards the end that stretches on for 300 meters.  It's completely dark in there.  Mel and I tried walking in with a flash light, got spooked, and ran back out.  Then we thought that was ridiculous, tried to go back in, went a little further, and then ran back out again.  Just as we were about to give up, a small group of fearless Chinese tourists went in like it ain't no thang, and we just followed along.  You may do better.

In the evening, we went to the end of the Ring of Craters Road, where you can hike over a field of lava flows towards the volcano opening, in search of some live lava sightings.  The lava rocks look pretty awesome, like flowing liquid that was flash-frozen.  It actually flowed right over some ill-fated roads, cos it don't care where you put your roads, fool.

There's no "path" to walk through the lava field.  Instead, they've set up six beacons over three miles, and you're supposed to just make your own way from beacon to beacon.  Unfortunately we only made it to the third beacon when we decided to turn back before it got too dark.  Turns out it was impossible to see surface lava that day anyway, and it will probably be impossible for you as well -- check this site for lava updates.  But hiking through the field was still a unique experience!

The next day, we drove along the Crater Rim Drive to catch some easy sights.  The views are stunning.

We recommend staying in the town of Volcano, right outside the park, for easy access.  Don't stay in Hilo -- it's still a drive to get to the park from there, and there's not much to do there anyway!