I did this last year as a thank you present for my parents for my wedding
(which was at Disney World) last September. I called the GF and got connected to private dining, and they'll send you a menu and you pick the foods you want (from appetizers, to side dishes, dessert, drinks). I got my parents crab cakes, caesar salads, and prime rib with mashed potatoes...not cheap, but they also have sandwiches, etc. so you can pick how much you want to spend. You can also get a butler for $50 which I did, and honestly I'm not sure how the meal would be structured without him, since he brought my parents each course.
My parents' dinner was at a private table overlooking the beach, but I think you can also have dinners in your room or on a terrace somewhere at the GF. My parents LOVED this meal and said they felt like royalty.
I also added a pontoon boat cruise during the MK fireworks ($125 per hour but you only need 1 hour). You could also get this cruise and they'll provide sandwiches, etc. The number for that is different though, I think its WDW-PLAY. Email me if you have any questions and I'll do my best to answer them.