There is such a variety of hikes in Oahu from bamboo forest, to rain forest, to waterfalls, to military look out stations on the mountains. Dont be afraid to hike in Oahu, some hikes are paved and some are not that steep or even very long for that matter.
One of my favorite hikes, about a 2.5 mile RT hike. The hike is very diverse, you start out in a bamboo forest, and work your way to a beautiful open field, and then on to follow a creek with a ton of rocks to climb. Make sure to wear some good water shoes because you will get muddy and wet.
Crouching Tiger\Lion Hike
Save Location Parking Here Place to enter trail
Nice short hike (.4 mile), steep, breezy hike with an incredible view. The parking and entry is a bit tricky on this one so save my map locations. Here is the trail to follow. If you enter where I specify and keep to the left when given an option, this will be the shortest route.