Hi Paulette,
Welcome back and I am delighted to answer your questions! Because you are staying at Disney's Art of Animation you will, indeed, have complimentary transportation available to you. Additionally, let me commend you on an excellent choice of Resort hotel for your grandson's first visit! The theming at Disney's Art of Animation will blow you away, as will the 300,000+ gallon Big Blue Pool with underwater speakers.
Your resort will have a bus stop transporting you to the theme parks, water parks and Downtown Disney. The buses will begin running 60 minutes prior to each park's opening times. Based on your arrival date, I've listed the park opening times
here.
I always allow 60-75 minutes prior to Advanced Dining Reservations to begin my travel. Although your actual travel time from Disney's Art of Animation via bus will only be 15-20 minutes, you'll need to account for the bus stop wait time and the walk to the restaurant.
Because it's your grandson's first visit, be sure to visit Guest Relations within the Parks so he can don a "1st visit" pin!
I suggested Chef Mickey's to you, and I will say part of the allure of the selection lies in the mode of transportation! A trip on Disney's monorail will delight ANY six-year-old boy! If you book your dining at Resort hotels, you'll need to travel from Art of Animation to a theme park, and then transfer to either a bus, monorail or boat to the specific Resort hotel.
The Cast Members are incredibly helpful in guiding you the right way, so if in doubt, just ask!
Another suggestion is to break up the day with an afternoon nap. Although it may seem wasteful, a rest from the heat will guarantee a bright eyed prince geared up for nighttime entertainment!
Wishing you a magical trip, Paulette, and feel free to contact me again!
Sherri