Well...during those dates and except for the 21st (closes at 8pm), IOA closes at 7pm so I doubt you would get to do much unless your daughter goes to sleep very early. If you aren't staying onsite or close to the park, you wouldn't give yourself any time to see anything. I think it would be a complete waste of money. You would be spending $85.00 for the IOA ticket and that's a lot of money just for WWoHP. I think you should wait until your family has interest in the Universal parks or when they will go with you so everyone can enjoy what Universal has to offer.
That's my honest opinion.
Agreed . . . is it possible you could send them off by themselves for a day (or at least a whole morning or afternoon/evening), and ask them to drop you off at IOA if they don't want to go?
I'm not sure what time your daughter goes to bed, but even from the closest offsite hotel, it takes 10-15 minutes to get to the IOA front gate, and another 5 minutes to walk back to WWoHP. Even if she goes to sleep at 6 and you immediately walk out the door, you will only have 40 minutes at most to enjoy the park. That doesn't really give you enough time to see all that WWoHP has to offer.
You'll want to go through the Hogsmeade shops, even if you don't plan to buy anything, just to see the theming. You'll also want to walk into Three Broomsticks/Hog's Head and possibly get some butterbeer or something - don't remember what time it closes, but a lot of the restaurants close 30 minutes before the park closes.
An adult could probably skip the Hippogriff ride, but you'll probably want to try Dueling Dragons and Forbidden Journey. This time of year, Dragons isn't a long wait; FJ, on the other hand can vary from walk-on to 45 minute waits that time of day depending on crowds. The single rider line can be very fast, but then you'd also want to go through the tour line at least once too, just to see the talking portraits and videos of Dumbledore and Harry, Ron, and Hermione. I spent 15-20 minutes on the tour just seeing everything in the castle.
If you're a superfan (like me), you might also want to catch the shows, including Ollivander's, the Chorus (with singing toads), and the Triwizard Champions. I'm not sure how late in the day those things run. Ollivander's usually requires a minimum 20-minute wait to get in, the others are outdoors so you can just walk up and watch them.
And the storefronts are fun to look in, just to see all of the details they've put into them.
Although it's geographically not a large area, they've put a lot into that part of the park, and if you're really eager to see it, you want to go when you have plenty of time to explore it all, especially considering the price of admission. I would either wait until your whole family wants to go together, or send the others off by themselves for a day and have them drop you off at IOA so you have plenty of time to see everything.
