Want to decorate a buttercream cake with fondant Christmas decorations and my plan is to place it  in a cake box , wrap with baking paper (like you would be a present) then wrap in plastic wrap and because I am a freak put that in a plastic bag haha. I believe it will be fine but tend to doubt myself. Has anyone had success or done anything similar. 

I have done exactly that numerous times. I place the cake inside of a box, seal well with packaging tape, wrap in saran wrap and toss it in the freezer. To thaw, I place in the fridge, still wrapped for a few hours. Move to the counter, still wrapped for a few hours, and then remove it from the box. It works perfectly every time. 

Exactly as she ^^^ said :)   But.... I put the boxed cake in a plastic bag...oohhh such a big difference  HA!!