Laura,
First off, I would not get the Park Hopper. I don't think it will be necessary with younger children. You should be able to do what you want, without having to spend the extra money. As kids get older, sure, but for now, no.
For an itinerary, here is what I would do;
- November 29 - Magic Kingdom
- November 30 - Animal Kingdom
- December 1 - Epcot
- December 2 - Hollywood Studios
- December 3 - Magic Kingdom
Make sure you take some time off in the afternoons, relaxing at your resort and maybe hitting the pool. That is crucial to keeping the kids' batteries charged!
That is an initial idea of where to go, and when. But send me back another question if you think this works, and let me know about what kinds of foods you like, and I can suggest some good restaurants as well!
Have a magical vacation!