We renewed our vows for our 10th on the balcony of OKW 2 bedroom privately; and then went to Epcot/France for dinner. Disney didn't know, and a friend of ours did the "service" so the only cost was that we picked up the tab for dinner for 8 people.
For our 20th we went on the cruise, and for $1500, you really do have a great time.
Good luck.
Cheryl