Start off at the Qantas first class lounge in the international terminal, then make your way to the AA Flagship lounge in Terminal 4 and end up at the Alaska lounge in T6, or try two of those three. They’re all good but in different ways (QF the best food/drink, AA the best views, AS convenient to your gate). All the terminals are connected airside but allow 10ish minutes to get from one to the next. Also since you have to clear US customs you’ll end up landside so you’ll need to clear security again, so you’ll have to go upstairs for that.