Graduation Cake - - traveling + buttercream = problems

I made the graduation cake for the daughter of a college friend.  Her colors were yellow and black.  They asked for marble cake.  Cake servings:  150

So I decided to do a 2-tier cake and 2 satellite cakes.  One satellite cake was 4" tall and the other 6" tall.   I also made about 50 cupcakes.   I did all I could for supporting the cake, making sure they were level, etc.  However, the jiggling of the car ride took its toll.

I'm not sure why, but I didn't take a picture of the cakes before we left.  Probably because I had about 3 hours of sleep and was not thinking.

We did take one picture of the cake after I started cutting the 4" tall cake (my favorite one).  

The cake that is cut had white frosting, the black polka dots all the way around, and then 1 yellow graduation cap amongst the black polka dots.  It was so cute.  

It also had the 2011 plaque as the cake topper.

A family friend was taking pictures and I know she took one with the graduate and all 3 cakes.  I'll see if I can get a copy of that picture.