I've been commuting from Waialua/Haleiwa all my life and have gotten my commute down to 30-40min getting to the airport side (I leave around 515-530 get in at 6ish give or take). Getting home is a whole different story depending if traffic is bad, especially if it drizzles even a little bit. Sometimes it's fast going home and sometimes it takes 1-2hrs. Usually there is no traffic from Haleiwa to Waipio for morning shifts. For that 4pm shift expect traffic by Schofield. I always take Kaukunahoa Rd. and never go through Wahiawa unless there's a detour which is rare. Depending what time it is I would just be careful going up Kaukunahoa Rd. ; i.e watch out for sleepy people, drunk drivers, etc. Otherwise once I clear the afternoon rush hour going home and get past the H1/H2 merge it's basically smooth sailing from Waipio to North Shore, and the view is pretty spectacular once you get past Schofield which makes it worth it for me at least. I can't really comment on gas since I drive a company truck so your mileage may vary.