We are only planning on spending one day in a theme park, but, fortunately for us, Disney World is more than just the theme parks.
Our list of things to do includes:
Epcot ($90 per person, though we're considering a Park Hopper so that would increase the price some)
Fantasia Gardens Mini Golf ($12 per person)
Downtown Disney (free)
Watching the Wishes fireworks from the Polynesian Resort (free)
Visiting Disney's Wildlife Preserve ($3 per person)
Seeing Brave on opening weekend ($10 per person)
Resort hopping (including, but not limited to, the Boardwalk and the new Art of Animation Resort) ( free)
That is less than $700 right now. I haven't included things like food or gas in the budget but we shouldn't spend too much on those because we won't eat out more than once (if that) and once we get on Disney property we can go anywhere using their transportation instead of ours.