Oooh, so many good ideas. DH proposed to me at the CR's California Grill, on the rooftop and during the fireworks. [And I was just excited that he surprised me with a trip to Disney!] There were other people around, I think, but they really faded into the background.
Really, any of these ideas would work and you're obviously a thoughtful and romantic guy. That said, I do admit to a fondness for a plan that allows you to have someone take a picture of the proposal while it's happening and/or directly afterwards. She might like the memento; it's the one thing I sort of miss. And there's a nice simplicity & elegance in the dessert/slipper presentation. That idea could be used or adapted, I would think, for your circumstances. Plus, that kind of public proposal might have the advantage of guaranteeing a photographer was around.
Of course, whether you want that public of a proposal depends on you, your intended, and your relationship. A public one really wouldn't have worked for me and DH; he is shy and was experiencing enough stage-fright without the pressure of a larger audience. And me, I'm just weird enough that I would have cracked inappropriate jokes; I can just see how I might have reacted to a public proposal. I probably would have blurted out something like, "But the baby's not yours!" as a joke to relieve the pressure. Yeah, that's me...humor in any situation. [For the record, I DIDN'T crack any jokes when DH did propose...but I did laugh. Out of delight and nervousness. Not everyone gets that about me. But DH does; I'm lucky.]
But more about you. As others said, if she has a favorite character or a special spot, that would be a nice marker. All the better if that spot or character already triggers an "our" place, an "our" movie, or a "relationship" moment. I also like the symbolic value of proposing in the MK, with a marriage that is fillled with fantasy, magic, dreams, that is filled with adventures and looks to tomorrow. Or at Epcot--with your desire to share both the World (showcase) and a Future with her.
Most of all, remember that whatever you do, she will love it because it comes from you. It's your relationship that's the most important thing.
Good luck and keep us informed!
some poor guy might get sucked into an engagement he wasn't ready for - although he would get lots of points!!! i always wonder that when I see names on the scoreboard at the stadium - what if more than one girl thinks she is being proposed to!!!!
