Howdy Elizabeth! I'm so excited for you! We stayed at
Disney's Animal Kingdom Lodge when our daughter was 4 and it quickly became one of my childrens' favorite Resorts. You will not be disappointed if you select Animal Kingdom Lodge.
My first suggestion to you is to stay in the Resort side and not in the Villas. It's difficult for me to say that as a Disney Vacation Club member but with twin 4 year olds, this is your best option. The Mara (quick service restaurant) is on the Lodge side as is a phenomenal pool.
You will be amazed by the number of locations where you can see animals at the Resort. My first suggestion would be to select a Savanna View room, though I will tell you that it was hard to get my children to leave the Villa at times.
There are public viewing areas outside the lobbies of both the Resort and Villas. There are Cast Members there who are animal experts and will be able to share seemingly endless information with you. This was one of the highlights of our trip.
Just walking down the halls to get to our Villas became a time of exploration for all of us. We have countless pictures of our children pointing to smaller animals that could be seen up close to the Resort (turtles, etc.).
You will have ample opportunities to see animals. Have your camera ready and be prepared to see the awe in the faces of your 4 year olds!
Like all Disney Resorts, Animal Kingdom is amazing. You will be on your own private African safari adventure with a touch of Disney magic!
Please let me know if you have other questions as you continue to plan your vacation!