I climbed the Waianae Valley Trail but copied this from a local blog site in case someone wants to try a different route (phone number handy for private property access.)
"Aloha, just wanted to share you you that we did this trail last week. It was a difficult trail, especially dangerous when it was wet and muddy/slippery, but it was well worth the effort. The last 1,000 ft section was 'no hiking' indeed, it was all 'climbing' and you will be on your hands and knees hauling yourself up the many dangerously steep inclines. But once you get up to the top, you will feel a great sense of accomplishment and you will be proud of yourself. That is a great feeling and the view is magnificent!
When you reach the gate of Kamananui Orchards adorned with "No Hiking" signs, you should really heed that sign. We met with one of the land owners ourselves and they are nice people who did not mind people on their land but they would like to be informed that you are coming. Think of it this way, if people keep climbing over your front gate, walk around your own home, and walk out your back gate, how would you feel as a home owner, especially if you have animals in your land? Really, please do call Randy or Mary at the Kamananui Orchard at 808-778-6014 and let them know that you will be coming at least 48 hours prior. If they are there when you arrive, they will probably tell you about the mac nut trees and other things they grow on their lands.
When you are up the mountain on the rope/cable section, always check the rope before you use it. One rope broke on us. Don't wear your pretty brand name hiking clothing and equipment if you can't stand getting mud on them. If you are a fairweather hiker, leave your shorts at home and go for long pants, especially on a wet rainy day. If you have gloves with good grippy material, use them on the rope/cable. It will make a difference. A walking/hiking stick is very handy on the hiking section but cumbersome on the climbing section so find ways to secure it. Ka'ala is a long hike. It goes up and up and up, and when you think you are done with the rope section, don't get your hope up yet as there will be more and more rope section. Go there early. An expert hiker can probably go up and down this climb in just about 7 hours. I have heard of people doing this climb in 11 hours. I don't want to discourage but I am telling you, if you get tired walking in Walmart Supercenter or you find the Diamond Head hike 'intermediate' then Ka'ala is not for you."
Thanks for posting this info on the Dupont trail access and also for your trip report on the Waianae route - good info and good advice!