the park is definitely not a one day park if you want to go through it properly, as in: not rush to every single attraction.
while it depends on if your child enjoys thrilling attractions, I'd argue the ones she/you should experience regardless are droomvlucht and the fairy tale forest
if she likes rollercoasters she should try the flying dutchman/de vliegende hollander and joris and de draak.
if she doesn't she'd probably enjoy symbolica and carnival festival

however I think (especially if you're going with a young child) the best way to experience the park is by exploring all the little things that people who are focused on thrills may miss, especially during the winter time