Birthday cake Challenge?!

Yikes so my daughter and I were talking about her birthday today. It's a little ways away but I like to plan in advance. So she wants to make cards at her party. Great I love card making. I can handle that. Then I say what kind of cake would you want. She says a mailbox. Mailbox? I am thinking are you crazy? But I look on line and yup there are pics of mailbox cakes. Oi! I am not sure I am up to the task. I need step by step instructions. I can not find any. Invent it myself? Yikes! I am not sure about that. Hmm. maybe I can convince her that she wants something else. Or maybe I will do it. Hmm dilemma's dilemma's.