Hi Holly!
Congratulations on your nuptials! Although I've heard rumors of guests finding ways to walk to Epcot from Disney's Caribbean Beach Resort, it's not recommended and wouldn't save you any time over utilizing the complimentary Walt Disney World transportation. As you surmised, Walt Disney World property covers over 40 square miles so walking to any of the Parks from Caribbean Beach Resort is basically impossible.
Because you are a guest of this Resort Hotel, the complimentary buses to and from the Disney Parks will become a valued amenity and convenience throughout your stay. It's one of the main reasons guests choose to stay on property! Who wants to worry about driving while you're on vacation? Let the friendly Cast Members transport you to your destinations! I'll provide you a link for more information on
complimentary Resort transportation.
As a side note, have you considered
customizing your celebration? Check out the link for romantic ideas to commemorate your honeymoon at the most MAGICAL place on Earth! Perhaps booking a carriage ride might be the final touch of pixie dust to planning an absolutely perfect honeymoon!
Wishing you a wonderful time, Holly, and please visit us again with further questions.
Sherri