they have a couples spa treatment at the grand floridian which is great, me & my fiance really enjoyed it & its so relaxing after a long day at the park. we also have enjoyed the illuminations & moonlite specialty cruises, you two will really enjoy it, its so magical! and we've done some of the behind the scene tours like dolphins in depth at epcot which is an educational encounter with dolphins and the backstage safari tour at animal kingdom, we've never seen giraffes & elephants that close, highly recommend either.
another suggestion is to always mention its your honeymoon, make sure its noted on your hotel reservation & mention when making your ps's and when sitting down for meals, our favorite restaurants are the world showcase pavilion venues at epcot like le cellier, alfredos, san angel inn, sommerfest, marrakesh & bistro de paris, also have dinner at cinderella's royal table at mk it has such a great ambiance inside the castle. and like others disers have suggested wear the mickey/minnie wedding ears they create a buzz amongst cm's & guests.
congratulations & have a great trip!