Lots of people want to prep apple pie with crumb topping ahead of time, especially around the holidays, but it I don't recommend assembling your pie ahead of time.  When you assemble the pie and let it sit, the crust becomes yet and soggy, and won’t crisp up during baking.  It is best to make your apple the day before so it has time to completely cool and set. You can place it in the fridge overnight (after it has cooled) and then pull out to eat the next day.  If you do want to make it ahead of time, you can assemble your pie and then freeze it before you bake it. This allows it to keep the same texture and consistency as if you just made it. If you do decide to freeze your apple crumble pie be sure you wrap it in a double layer of foil before putting it in the freezer.