Good points, CN, and combining the trip is really the way to go. And you know my post was tongue-in-cheek.
But yeah - there is plenty to do and see in and around LA, and if you've already tentatively planned on the trip, then by all means. And not to get too philospophical on you, but do stuff like this when you still young and more free to do so. Its funny - when you're young, you have more time and freedom, but less cash. When you're old, its the other way around!
There are one or two hotels in the city of Lake Forest - one is a Holiday Inn, I believe, and should be fairly inexpensive. It is less than ten minutes from teh pary location (I know - its in my home town and on the way to the party for me!). Play your cards right, and you may even be able to arrange rides. Who knows...
I am / have been good friends with a level designer at Blizzard, but before you get worked up, I haven't been in touch with him for a couple of years, and it would not be appropriate at this stage for me to offer his name or to even contact him simply for this. He is a member here, but not very active. But it may not hurt to throw a call out in the OT for any industry pros.