Vista Cay resort is only one mile from SeaWorld. Stayed there in December in a 3 bedroom / 3 1/2 bath for around $125 a night. We really liked the proximity to both Sea World and Universal.
Another vote here for HGVC (Hilton Grand Vacations Club) @ Sea World. It's right across the street and a very nice resort. We will be there in 27 days!