This is a lovely small park on a cinder cone with a nice overlook.
Near the entrance is the trail head for the 'Ualaka'a Trail.
If you follow the road up the mountain you come to a large parking lot with a restroom and several shelters and picnic tables. From here you can continue to follow the road or park and walk past the restrooms on a short grassy path to the overlook, where there is a small parking lot. Both times I've been here it hasn't been particularly crowded.
You can get a pretty good view of Diamond Head from the overlook.
As well as a good view of downtown Honolulu.
Here's a great view of Manoa Valley.
There are two ways to get here, which I'll cover in a there and back again post later.