If you decide to drive up on the day rather than get your last hotel at LAX and don't already have the Waze app, I'd recommend it. You'll not only be able to see real time traffic but it'll tell you how to avoid it. The drive will likely be miserable no matter what time you set out, but at least if you head up early you'll have very pleasant lounge options to pass the time if you get lucky and the traffic is mild. I usually allow four hours drive time but I'm risk averse and have had to face begging to queue jump (getting in with one minute to spare) when I used to leave three hours before check in time. On lucky-drive days, I just lounge hop as everything's connected airside now. The Flagship in T4 is no QF F lounge, but very nice if you fancy a walk and a change of scenery. Good food and free pour drinks. Keep in mind that TBIT security can commonly be 20+ minutes.