W.K.
Have you looked at allears.net - I LOVE this site for everything Disney. We were just there last week! My daughter is 9 so she got on everything she could. We stay on property all the time so we cant answer the whole shuttle thing, I know there is an area where the shuttles drop people off which is different for every park. At the kingdom its right at the gate. Taxis can drive up to the gate too, unless you want to ride the monorail or the boat to the kingdom you can ask them to take you to the transfer station. Everything is based on height so depends on how tall you child is. One year I had a shrinking child, first park she was tall enough, next day she wasnt. It was a crazy week.
Many people I know with younger kids go to the park for a few hours, return to the hotels for naps and snack and return later in the evening to see the parades at night. You ticket will allow you re entry for the day. If you have a hopper then you can do anything.
There is still a lot of construction going on in the Kingdom cause they are building a new fantasy land. On one side of fantasy land they used to have Mickey and Minnies 'home' but we didnt look this time around so I cant say if its still there. The little Einstein's are found in Hollywood studios. They have this building with shows all day long which have the characters for the younger kids. Doc Mc Stuffins? Well cant say I heard of him lol.
Check out allears.net you may find it easier to navigate.