Eventually, I reached a towering set of powerline poles and soon thereafter is a fairly distinct trail that heads off through a thicket to the right. That trail is Haihaione/Mauna o Ahi. Actually, the ridge the trail is on is Mauna o Ahi. The descent is somewhat steep but ample trees and footholds are available to make the downward trek manageable.
The Hawaiian Trail and Mountain Club uses this route for a hike so the way is cleared periodically and ribbons are affixed to trees on the way down.
Eventually, when the ridge leveled off, I reached a junction with an old jeep road that went off to the right and descended to Kaalakei Valley. For some reason, I opted not to head down along that route. If I had, I might have found a trail that climbed back up to Kuliouou Ridge at a point right near the picnic shelter. I'll have to go back and explore that option at some point.
Anyway, instead of heading right on the jeep road, I continued along Mauna o Ahi ridge until I reached another ribboned junction where a trail headed left and down toward Haihaione Valley. This trail I took, and after a couple of switchbacks, I had dropped down considerably into a semi-lush forested area that seemed to be used by paintball enthusiasts and/or teens for drinking parties (plenty of bottles/trash in the area). I recollect crossing a dry streambed and eventually arrived at civilization at the terminal point of Haihaione Street. There's a vacant lot so trespassing isn't an issue.
There are other options for hiking the Haihaione Trail, of course, including going up instead of coming down as I did. One might also ascend Mariner's Ridge and, left at the crest, hike for 1 to 1.5 hours, and then descend Haihaione.