answer:From Baking 911: “Large cakes should be transported in pieces rather than the whole stacked cake at once. Put each tier in its own sturdy box. If you have any delicate decorations, do not put them on until you reach your destination. And, always take a repair kit with you if there are last minute touch-ups required. When transporting a cake, shade it from the sun. I made a wedding cake which had to be transported about an hour’s drive away. I had it in the back of a van, which, of course, has many big windows. The color in the flowers on the side facing the back window faded in the sun. By the time we arrived, there were two very distinct sides to that cake!” Here is another detailed article from the folks at Wilton. And, finally, from the Cake Channel.