I wrapped each piece up separately in brown paper and tied it with baker's twine. I included a number tag that I stamped in order for them to know which one to open on which day.
As the days count down to Christmas morning, my nephews will see the Nativity being built so that on Christmas Eve it will be complete.
I plan on just putting all of the wrapped pieces in a red box from Michaels and mailing it to them.
I cannot wait to see their faces...