Hi Beach mama,Wow what a cool cake to try. I'm no expert but as long as you use a firm cake with a nice stiff filling (not jam!) which is well chilled you should be right. Semi freezing the cake before carving is a great idea. Don't bother cutting the overhanding eaves, create the overhang by layering up the frosting instead.Use dowls into the board if you're worried.best of luck!