... if the carriage is rockin'!
I've read about carriage rides around the grounds of the Port Orleans Riverside resort that are supposed to be quite romantic and beautiful. You might check into something like that.
Otherwise, it might just depend on your significant other's tastes. For example, if your wife-to-be has fond memories of campfires and smores, heading over to Fort Wilderness for a snuggle on a hayride followed by smores and a movie might be fun.
It might also be fun to create a scrapbook of your "honeymoon around the world" by touring Epcot and having passersby or cast members snap a romantic photo in each of the different "countries."
A great place for a romantic dinner and then a stroll around the grounds is the Wilderness Lodge, where you can eat at Artist Pointe, and then take in the beautiful grounds.
You could also rent a boat for one of the Illuminations cruises. A bottle of wine, some cheese and thou under a sky filled with fireworks...
Or snuggle up on one of the resort beaches and take in the nightly electric water parade. Maybe curled up in a hammock over at the Polynesian?
Pick up the bride and groom mickey hats at one of the shops. People will be congratulating you left and right, and she'll feel like the star of the show!
Of course, no matter what you do, it's sure to be a fantastic trip!
Richard