Oh yeah, forget that, just let them loose in the park. If they don't have something that gets them early entry into the park, tell them to head straight back to HP, and ride Forbidden Journey if the line is under 90 minutes. Since it's prone to breakdowns, the line will only get longer as the day goes on, and if they don't ride it when they can, they may miss it. Dragons next, front row of Ice (or whatever they're calling the blue one now) and back row of Fire are best seats. There's a re-entry cut through as you leave the ride that keeps you in the castle so you don't have to walk all the way out and back in again. If they're really into HP, they should ride Flight of the Hippogriff, cause it's some pretty cool themeing. JP, ride River Adventure and run around Camp Jurassic if it's cool enough (yes, it's a kids playground, but trust me, it's fun to explore). If they don't want to get soaked, skip Blutos, but Ripsaw is generally OK. Spiderman is worth about a 45 minute wait, Doom I wouldn't wait more than 10-15 minutes for, it's fun but not that long. Hulk front row is awesome, but I'd stay away from the back row or two, they're pretty rough. Storm Force Accelatron is basically the Tea Cups ... would have been 100x better if they'd put it inside and had a light show going at the same time. Cat in the Hat is always fun, as is the Caro-Suess-el if you catch it during boarding times. One Fish Two Fish is a skip unless the line is really short, it's got a horrendous load time. The sky trolley (I don't remember the new name for it, originally it was going to be ::deep breath:: Sylverster McMonkey McBean's Very Unusual Driving Machines) is pretty cute, too, but again, skip it if the line is long. If I Ran the Zoo is cool to wander through, too (of course, I don't know the ages or interests of the teens), and there are all kinds of neat things to find on Seuss Landing (by the way, there are no straight lines in the architecture of Seuss Landing, ignoring the lines in concrete of course ... even the trees are bent, they came from an area damaged by Hurricane Andrew). Poseidon's Fury is a great walk-through, even if it is a bit cheesy; the water vortex and the fight effects are awesome. The 8th Voyage of Sinbad is a stunt show, and is rather impressive if they are there when it's about to start. For food, I recommend Thunder Falls Terrace in Jurassic Park, their BBQ wings are to die for.
If they get souvenirs, they should ask about package pickup, so they can just grab them on the way out, or wait until they're about to leave so they don't have to lug them around all day. Oh, and make sure the memory card on their camera is empty, and the battery is fully charged ... if they're HP nuts, they'll be taking a *LOT* of pictures.