Hi Yvonne!
If you are not planning on visiting 2 parks in one day then you do not need the park hopper pass. Your base tickets are all you need. I have made you a list of some rides at both parks that I think your children will love.
Magic Kingdom - The Many Adventures of Winnie the Pooh, Dumbo the Flying Elephant, Cinderella's Golden Carousel, Mickey and Minnie's Country House, Donald's Boat, Monster's Inc. Laugh Floor, PhilharMagic.
Animal Kingdom - The Boneyard, Finding Nemo the Musical, Kilimanjaro Safari.
There are afternoon parades at both parks that are performed daily at 3:00pm that your kids will love.
Have a magical time!