Tomorrow is a holiday so mummy and daddy don't have to go to work!
Tomorrow is Saturday so mummy and daddy don't have to go to work.
Mummy and daddy don't have to go to work tomorrow because it's a holiday.
「明日はお休みだから、パパもママもお仕事行かないよ!」= Tomorrow is a holiday so mummy and daddy don't have to go to work! / Tomorrow is Saturday so mummy and daddy don't have to go to work. / Mummy and daddy don't have to go to work tomorrow because it's a holiday.
「君も保育園行かないよ!」= And you don't have to go to nursery tomorrow either!