You can always make extra Challah dough to freeze and bake at a later date. There are two ways to do this; both give excellent results.
Method #1: Wrap leftover dough tightly in three layers of saran wrap. Thaw when needed for at least three hours. Kneed, allow to rise for two hours. Shape and bake.
-OR-
Method #2: Allow dough to rise, shape into loves, place in freezer until hardened, wrap in saran wrap in three layers, freeze until needed. When thawing, remove saran wrap, allow to thaw/rise for three hours, then bake.