Sorry for the late reply. There are tons of good spots to hike that aren't going to be over run. Some of them are hard to find others aren't that bad. Depends on what you want to do. Check out this site.
Linky They have some good trails.
What day are you thinking of going??
I was thinking of possible going out somewhere on Sunday. Stair way to heaven was revamped and is supposedly safe its just not offically open. You will need to park at Windward community College to the trail head which I am not too sure where it is. Might want to try and google it. For something sort and easy check out Aiea Loop, there are some nice views of the Halawa valley. Or if you want to do something longer and with some water falls and what not check out the back of Palolo valley. That trail can be dangerous but it is well worth it when you swim in the water falls. This trail isn't that hard to find and you can go a long way back on it you can easily do a full day hike on it.