If you have a little flexibility in your dates this might be worth doing- amazing how much cheaper a holiday can be just by going a day or two earlier/later.
i've done is a spreadsheet with possible dates, and the cost of flights, tickets and accom for each option. I did the same for our other trips - why? Because sometimes the more expensive airfare lined up with dates for a good deal on the accom portion. i.e. free dining promo at WDW, which when you have teenagers, means a pretty good saving. I'm waiting for Brisbane travel expo to see if I can get a better deal on flights from Central Qld to LA, but I already have my preferred option and costings done so I can book if the deal's a good one.
if you're going to do Universal, it may be worth looking at saying there for a couple of nights - We did 2 nights/3 days, buying one AP to get a 30% room discount, and by staying onsite you get into HP world an hour early, and free FOTL passes for everyone.