South Point is the southernmost point in the entire United States, so we HAD to go there. How can one visit Hawaii and NOT go there? (It's a traveling thingy for us...)
To get there, take South Point Rd from Highway 11 (between mile markers 69/70). This is a narrow road, and sometimes you wonder if you're on the "right" one, but face it, there aren't any others... so it's right. When you face oncoming cars, one of you must pull over, but it's fairly easy to do.
On the way you'll pass a wind farm. If your windows are up, put them down for a tad and listen. The sound the windmills make is different, and neat, though I'm not sure I'd want to live near them and hear it all the time! The wind makes some of the trees grow strangely too, so keep your eyes out and you'll see them on your way.
After 4 miles (or so) you'll reach a fork in the road - stay right. Soon you'll reach a parking area with lots of people at it. If it's a day like we were there, you'll also see youngsters (and a few oldsters) jumping from the cliff into the sea below. My boys wanted to. Dad didn't want to go with them (Mom either) so they left disappointed. Other tourists were joining in. There's a shaky looking ladder to climb back up.
There were also fishermen there, and general picnickers. Beware though—this ISN'T the southernmost point. To reach that, head to your left (looking at the water) past a spot where ancient Hawaiians tied their canoes (looking at that along the way), and follow a rock wall as it gently goes down into the ocean. That's the TRUE south point. When we were there, someone had written (in coral) both an arrow pointing the direction to go, and the words "You are Here" when you finally got there. Quite a nice tip, and confirmed by the guidebook.
The view from here is amazing... and we spent a bit of time walking around and reflecting of exactly where we were on the globe at this point in time. (Another travel thingy!) If you have time, go there; if for nothing else other than just to say you've been! It's free.