Hi Rebecca again! I know the transportation can be confusing when trying to go from resort to resort. In your last question I explained your options of how to get from your resort to the Boardwalk area. It means changing at a park to make a transfer and my suggestion is to bus to Hollywood Studios and then catch the boat to the Boardwalk.
Now for your next transportation question about getting to the great
Chef Mickey's at the Contemporary Resort from the Magic Kingdom. This is actually an easy trek as you can either walk it which would take you about 10-15 minutes or you can hop on the resort monorail and get off at the first stop which is the Contemporary Resort. Chef Mickey's is on the 4th floor and that is the floor you would be on when you exit the monorail area so that is very easy.
To return to your resort you would want to repeat your steps and head back to the Magic Kingdom to catch your resort bus. You can either walk back or take the monorail all the way around and get off at the park. Please be sure and check the resort monorail schedule as from time to time they will shut down for maintenance work.
When you arrive at Chef Mickey's please let the attendant know that you will want a birthday cake. They have either chocolate or vanilla small cakes available at all times. You can also pre order something bigger to have delivered but I have found that then you will have to carry around the left over or it goes to waste. You can always do something for the room back at your resort where you can easily keep what is left.
Walt Disney World is a fabulous place to celebrate and Chef Mickey's will be very special. All of the characters will make it a point to bestow birthday wishes to your son!