Hi Jane,
Wow, your daughter/son-in-law sure are busy! I am a mom to twins(7yrs old) and a single(9yrs old) and I know how busy it can get with us.
The Boardwalk Inn is a wonderful choice, they will really enjoy it!!
If they don't want to bring strollers you can rent them at any of the parks. I am not sure how long they are planning on staying. The boys will enjoy visiting all of the parks and they can easily spend a day or more on each park. When they arrive, they will need to pick up a Times Guide so they can see all of the show, parade times. Character meet and greet locations as well as the extra magic hours for each of the parks.
Character dining is always a fun way to meet and see your favourite characters. They are a short walk over to Disney's Beach Club where you can dine with Mickey and friends at
Cape May.
Depending on when they are visiting in December,
Mickey's Very Merry Christmas Party happens certain evenings during the holiday season.
If you have any other questions, please let us know.
Carrie