What time do you want to arrive is the real question? Arriving at 4am would give you plenty of time to get through security and settled before the race. If you really want to maximize sleeping in, you could aim for 5am which would still give you plenty of time to make it to the start line before it closes but you'd miss all the pre race spectacle and possibly your assigned corral.
There aren't any road closures and there are fewer participants for the 5k so the traffic doesn't get backed up like it can for the half and marathon. The drive should only take 10-15 minutes. The walk to security and the start is approx 15-20 minutes. Once you decide what time you want to arrive, plan for 30-40 minutes from your resort to the start line.