Hello, Ann-Marie!
What a wonderful way for you and your parents to celebrate their very special anniversary!
I called Member Services for you and the Cast Member I spoke with suggested that you check in at your resort, then take your Key to the World Cards to the Concierge and purchase your park tickets at that time. In doing so, your park tickets will simply be added to your Key to the World Cards. (I was told that this is a
shorter process than if you had purchased your tickets prior to arrival and need to have them added to your Key to the World cards at check-in.)
Don't forget to get your parents their complimentary "Happy Anniversary" buttons! They'll smile even brighter as Cast Members and complete strangers throughout their stay wish them many more years of happiness together. In addition,
consider surprising your parents with something special from Disney Floral & Gifts. You could also surprise them with a delivery of
a specialty cake at dinner. To order a custom bakery cake, just call (407) 827-2253 at least 48 hours in advance; customized cakes can be delivered to most Walt Disney World table-service restaurants.
Have a wonderful vacation together! Please send any additional questions you may have as you plan this most special family trip! I'd love to help in such a wonderful event!