Sunflower Cupcakes

Several weeks ago I tried another design from my new book Hello, Cupcake! I went to a ladies' brunch hosted at the Botanical Gardens so sunflowers seemed to really fit in with the theme.
The sunflower bodies are Oreo and Mini Oreo cookies, and the petals are a mix of yellow and orange buttercream. I found green cupcake liners in a set of with purple, red, and blue liners. The cupcakes turned out really cute but were definitely more work to make than the butterfly cupcakes. After piping each individual petal my hand felt like it was about to fall off.
I love my Wilton cupcake stand. I was able to transport the stand disassembled, assemble it at the brunch, then top with my cupcakes for a beautiful presentation.
One problem with making these specialty cupcakes is that it's hard to keep them fresh. I like to make them over several nights- make the cupcakes one night, the icing the next, then lastly decorate them. Once the cupcakes are decorated they don't fit in my cupcake carrier very well. These sunflower cupcakes tasted pretty dry. Any advice on keeping them fresh for the day of the event?