Hi Heather,
I just returned from a stay at
Disney's Animal Kingdom Villas - Kidani Village. It is such a lovely resort! My daughter had a great time going out on the balcony of our villa overlooking the savanna to see how many different animals she could find throughout our vacation. I bet your little ones will love that as well!
I do recommend that you use your car to travel from Disney's Animal Kingdom Villas to the theme parks. You are correct, Disney's Animal Kingdom Villas are geographically fairly far away from many of the theme parks. Taking a bus from Disney's Animal Kingdom Villas to the theme parks can take a lot of time.
We almost always rent a car when we visit Walt Disney World, and we almost always drive everywhere that we go at Walt Disney World. Especially from a resort such as Disney's Animal Kingdom Villas, I think that you are going to save time by driving. It is really easy to drive around Walt Disney World - you do not need directions to get anywhere, just follow the signs and you will get where you are going. As a Walt Disney World resort guest, you will also not need to pay for parking at the Disney theme parks - just be sure to display the parking permit that you receive upon check in at your resort.
I hope that these thoughts help, Heather! Have a great time on your trip - it is coming up so soon! Please do not hesitate to ask if you have any further questions.