It looks pretty good from far away -- from up close you can see my mis-steps. Here's all the things I would do differently!
1) Frost the cake on a surface where you do NOT have to transfer the cake to a cake plate. When I transferred the cake to this pedestal stand...ugh. It was not pretty. I was able to mostly fix it but it would have been easier if I hadn't.
2) For me, a five layer cake took a little more than the large tub from the cake store -- maybe a little more than a 60 oz tub. This might just be because I was inexperienced but still...I had to go back to the cake store to buy more. (I didn't make the icing!)
3) If you are going to dry fondant and cut it into into shapes (as I did with the rectangles for the castle)...make them thicker than what you see. They broke very readily at the top and I ended up with fewer than I made.
4) Using edible images seems like a great idea - but somehow ( I didn't check how to fix this) the image sagged on the cake side after application. And movement of the image immediately rips it. So -- be careful when applying and make sure you are in a very cool place.
5) When using cake characters, make sure that you can attach them securely to the cake for transport. ALL of the characters except Dorothy fell off the cake during transport. What a disaster. I had a good attitude, and was able to mostly fix it -- but still disappointing. I think it was in great part because of the very hot weather and very hot car during transport. Next time, I will do this differently.
6) I did not make the fondant rainbow on top. I ordered that from an Etsy seller from Canada. The site is below. Order in advance - it takes a while to get here unless you pay for expedited shipping.
I guess that's about it. Bottom line. It was worth it when Abby saw the cake and was so delighted. And when I cut the cake and she saw the rainbow...she said "Wow!" Perfect!