Here I am to your rescue!
Get this, I met my wife at DisneyWorld. I met her just across from Crystal Palace at a circular area with a place to sit with vegetation in the middle. We watched Fantasy In the Sky. I met here there during Fantasy In the Sky. She was so pretty and single and I was single as well. I lived in NC and she lived in South Fl. We talked and then met back up at the park the next day and hung out.
When it was time for her to go back home she actually cried. We were hitting it off big time. We shared our first kiss at the parks and did so on Haunted Mansion of all places, where she kissed me first (I never get to hear the end of it). We talked on email, then phone, then webcams and phones. I flew to see her for a week then she flew to see me for a week. Before you know it, I moved to South Florida to be with her. We went back to Disney and I asked her to marry me there, in the same spot, during the same Fantasy In the Sky show. Then we got married one year from the time we got engaged and we spent a 2 week honeymoon at Disney as well.
Now that you've heard my story. Here's something very romantic that you should do. All proposals should happen in the evening at the Magic Kingdom. Use the day period to just enjoy the fact that you know what's coming. use the day to "butter" her up with super romanticism so that when the evening rolls around, you can pop it and WOW have you built it up well.
I would spend the whole day doing everything for her. Buy her things that she wants. Offer her things. Share a milkshake, etc.
firstly, for dinner, go to Cindarella's Royal Table. Get PS. It's very low lit and romantic. YOu must go after dark as the atmosphere is even better since the daytime is much brighter in there with the huge windows on the back side. Share a milkshake, (since you get to keep the pretty glass with the restaurants name on it, great keepsake for the day you got engaged) and the leave the restaurant and get a nice spot for the fireworks. DO IT A LITTLE BIG AWAY FROM MAIN STREET TO AVOID SHOULDER TO SHOULDER PEOPLE. Do it off to the side where you can SOMEWHAT have your own little area (if you are a shy person) and ask her there during the show.
If you are not a shy person and really want a big effect. When you make your Ps make it known (and especially with your waiter) that you are going to pop the question in the restaurant (only after dark). Give them the ring and they will bring it to your table as she least expects it and hand it to you to give to her. If you want I think they will even bake it in a small cake (but I would never do that). I would say do it in the restaurant by letting yoru waiting bring it to you after the meal. You will get a huge ovation in there from everyone. Who knows, if you let them know far enough ahead of time, you may even be able to get a character or two in there for the big question.