During our trip my group decided to do KoKo Head trail. Plenty of parking, but earlier you get there the better, heat, humid and hiking, don't always mix well together. I was sick this particular morning (maybe something to do with the night prior 🤮) I do not recommend the night prior activity..LOL. But I said I was going to do it and I did. The climb is steep and you definitely need to watch your step. There are parts along this "railhead" you could acually fall through and really hurt yourself.
It is a tough but doable climb, I was complaining about my sickness until I saw a lady breeze by me while carrying a baby on this hike...DAMN. After that, yep, no more complaining. At the top is a great view of Honolulu and most of the east side of the island. This would be anyone's idea for a prime sunset or sunrise photo opportunity.
If you do go during limited visibility hours take some light with you, it can be dangerous during the day and likely treacherous footing in limited visibility. At the top of the climb is a pillbox, go down into it, its pretty cool.
Not necessarily a "Must do thing" but if you are going to hike while in Hawaii, THIS is the "tough visitor" hike to complete while you are here.