I want to say right up front that this was not an easy hike. In our research to find out what this hike was like everything we read made it sound just slightly challenging. We read several blogs that described the route fairly well. My only issue with all of these articles is that it is often described as follows: "Once you begin the steep descent, be careful because it can be slippery even on days when it hasn't rained. Fortunately, there are a sufficient number of trees for handholds and rocks and roots for footholds to make the climb down to the gulch negotiable." Well that doesn't sound too bad does it? Let me tell you the truth.
My friends and I, along with my two small dogs did this hike during the summer. We figured that because there had been hard rain recently there would be a waterfall at the end. The beginning of the hike, starting from the Aiea Loop trail is not very difficult. It wasn't hard to find the spot where the trail veers off of the loop. In the beginning it's a very pleasant trek through the trees (for more detailed directions I recommend the Hiker's Guide to Oahu or doing some web searches. This site is okay for most of the directions: http://www2.hawaii.edu/~turner/hikes2/kalauao.htm .) We found all of the markers fairly easily, although I didn't know what a mango tree looks like and would have missed the right-hand side turnoff if my friends hadn't pointed it out. I would suggest looking up mango trees before you head off on this one, so you can find several of the turn off points. Once you turn off down into the valley, this is where I feel like people have been a little deceptive about this hike. It got VERY steep. Yes, there were handholds and footholds, but it was not so much a hike down as a climb down. My dogs are very good climbers, but they had a lot of trouble on this portion. We had to help the dogs down, and help each other down some very slippery spots. At least the trail was easy to follow at this point. Finally, we reached the bottom of the valley where the stream is. Before you head upstream, make sure you make a VERY obvious marker for yourself to turn onto the trail, especially if the stream is dry. There was a pink ribbon tied to the tree at the turnoff, so we thought we were good, but we missed it on the way back.
Unfortunately, for our hike, the rain hadn't been enough for there to be any water in the stream. My dogs, of course, immediately jumped into the first little pool of water they saw, which was nasty and smelly.
As I said before, we saw there was a pink ribbon, so we thought we were good and headed upstream towards the waterfall. Instead of crossing back and forth 8 times like all of the directions said, there was no water and we found it easier to walk on the rocks upstream. It took a while, but we made it to the "waterfall" and "swimming hole." It was totally dry. I don't even have pictures, because we were so tired at this point and so disappointed. I would love to see it with water. Wait until winter to do this hike.
After taking a break, sitting down and drinking some water we turned around and headed back. Again we stayed on the rocks and kept looking for the pink ribbon to indicate our turnoff to the left, to head back up to the ridge. We missed it, totally. And of course, we didn't realize we missed it, so we went way, way, too far down the stream. If you do this, you will notice that the path on the side becomes very obscure. It doesn't disappear though. There is still a faint trail following the stream past your turnoff point. This is part of why we went so far. Anyway, hopefully you will follow our advice to make a very obvious marker for yourself to mark your trail. Another group following us had left their bikini bottoms. I don't necessarily suggest you strip down and tie your clothes to the tree, but I kind of wish we had. We had gone really far out of the way, Jak fell down and got a huge bruise on her back and my dogs were super tired. We also began to run out of water at this point because the trail had been described as "nice" and "suitable for novice and intermediate" and we underestimated our needs. I ended up having to carry my dogs for most of the trip back. The climb back up was pretty tough. Like I said before, it is really steep. A lot of difficult climbing was involved to get back to the top. When we finally got to the ridge, it felt really good. We were exhausted and dehydrated but the rest of the trail is pretty easy, all the way back to the trail head.
I think my main issue with this hike is that other articles made it sound easy, so we were not prepared for the trip. If I was going to do this again I would bring more water and make sure everyone had their own water bottles. I would bring something to mark the turnoff points to make sure we didn't miss them. I would go in the winter, or when I was sure there would be some water. I wouldn't bring my little doggies. A big dog would be able to handle it, and my dogs made it, but they weren't happy. The steep climb was just too much for them. And they love hiking. I think the climbing portion is totally doable and could have been fun, but be prepared for it.

We did this hike this morning. The adventure began with an urge to climb the "stairs" that you can see when you drive Kalani`ana`ole Highway, near Haunama Bay. We began to do some research into the hike. We knew it was on Koko Head, so we searched Koko Head hiking trails. With almost all of those searches you come up with a different trail that starts at the Halona Blowhole lookout. We just wanted to climb the railroad tracks. After some research and some help from a friend we found out that the hike starts from the Koko Head District Park (423 Kaumakani Street) behind the baseball field. After a few wrong turns we figured out:

Turn onto Lunalilo Home Road towards Koko Head off of Kalani`ana`ole Highway. Take the first right hand turn. This is where, of course, my directions were wrong and instead of turning I went all the way to the end of Lunalilo Home Road. Don't do this. Take the first right on Lunalilo Home Road. This is Kaumakani Street. Then look for the road to the baseball field on the right. It is on aptly named Koko Head Park Road. Don't worry if you miss it, since both of us did the first time. There is actually a pretty obvious sign that informs you that this is the park. But don't feel bad if you don't notice that the first time through. Drive into the park and go to the last parking lot in front of the baseball field. Again, don't worry if you miss it. The road actually ends and you will just turn back around and Viola! There is your parking lot.

Walk up to the paved path on the right hand side of the baseball field and start walking towards Koko Head. Follow the dirt path on the right hand side that veers off the paved pathway. I assume if you miss it you will just walk around the baseball field. Probably also a nice little walk. From there don't be tempted to follow the dirt paths going off to the side. You will see where the stairs begin. If you're like us and need really, really specific directions, ask everyone you see. People here are all very friendly and won't laugh at you for asking. (Well, most of them won't laugh)

It's all uphill from there! Literally. You just walk up 1048 steps to the top. You will be very hot and very sweaty. Bring water and take lots of breaks. There are two areas where the ground drops off under the railway and it can be scary for someone who is afraid of heights. It also is a little flimsy in spots. Always check before putting your full weight. Although someone seems to have replaced some of the railway ties, you are responsible for your own safety. It took us about 40 minutes to the top, where there is a great view. It's worth checking out the bunker, the old radio tower and the old remains of the tram. You can crawl on all of the stuff to get some good views. Be careful though, use common sense. Or ask someone else around who looks like they have some common sense. It's fun to play on the old buildings and the helicopter landing, but test it first.
When you're done, head down! Down takes less time, but is still a hell of a workout. Watch out for joggers and children who seem to have inhuman agility and magically race down the hill. The crossing where the ground drops away is a little scarier on the way down as well, but don't be afraid to crawl. "Drop down and get in between." That was the advice given. When you get there, you'll know what to do.

Overall, I think this was a fun hike if you are in average shape. It is not easy, but it is not impossible if you take it slow, wear sunscreen and drink lots of water. The view is worth the stair climb. Also, it was a quicker hike, I've read that it takes most people 45 minutes to an hour to reach the top and it took us 20 minutes to reach the bottom.