I used to live in Kaneohe Marine Corps Base for about 4.5 years, and also in Kaneohe town and Kahala before departure...
From my experience, depending on hours of the day, you can make the trip across H3 (the fastest way most of the time) to the town in around 25 minutes. From the main hospitals, maybe add about 10 more just for traffic in town. But the highway goes quick, in regards to no heavy rain or accidents in the tunnel.
It's one of the best places I have ever lived to be stuck in traffic, tell you that, I still remember coming down the Pali Highway and seeing the water level higher than the building level (due to going downhill) It was really beautiful.
I would say in the thickest of traffic, meaning accidents, people driving slow and stupid, and even H3 kinda plugged, I wouldn't plan on more than an hour to get home. It's a quick jaunt once you get on H3. Enjoy your aina!
ADDED: I lived in Kahala, just about ten minutes down the K(reallylongtosay) Highway...Kalananiole (butchered, I know!) Right when H1 ends, it's pretty fast paced, and the H1 tapers off to the K with little to no warning, from then it's a decent short drive to the area. I lived in Kahala Kua for about half a year...(got lucky I Know, found a nice quarters up there on side of a house, and still to this day, have not found a better room for the money in Key West!) I will tell you when I went into town, it seems to be a real congested spot during rush hour, after work and in the morning. But H1, like H3, moves pretty fast, and the most you may see is a mile of slow moving traffic-still, no horns! Not bad for a large city like HNL. Anybody from SO California can chime in now, if you have been on the 405 in rush hour...YIKES! Once was enough for me!
Nick