Just thought of something...if you're foodies and since you're planning to go to Napa Rose anyway, you might do the chef's counter there. You can make reservations pretty far in advance (I think I've done it over 60 days), but you can't do it online. Call the restaurant directly (I think I found it online last time, but otherwise, just call the Grand Californian directly and ask for it) to make a reservation. There are two seatings, I believe, 5:30 and 8:30, and the chef's counter is small so you want to call early. (If given a choice, choose the chef's counter over the "dessert counter.")
There are a bunch of threads on the boards about the whole experience, too, but the gist of it is that you can choose a preplanned tasting (paired with wines, if you wish) or you can leave it up to the chef to decide what you are going to have (after you have expressed to the server what you would prefer not to it or have a food sensitivity to--for instance, my husband will eat pretty much anything, but I'm not into organ meat and won't eat octopus in front of my son, who is uncommonly fond of octopuses and thinks eating them is barbaric. Yeah, he loves cows and eats burgers, but he says that octopuses are way too smart to be eaten.)
If your 13-year-olds are all interested in food and watching it be prepared or have ever watched one of those cooking shows, they'll probably be enthralled. (We've been doing it with our kids since my son was 6 and my daughter was 9, and they love it!)