Can I fill a cake on Thursday and cover in MMF and leave out over night for Friday or do I have to refrigerate it? I've never used MMF before and the cake is just a sheet one, will something happen to the MMF if its refrigerated? If I can't refrigerate could I substitue the cream cheese for a buttercream filling for overnight storage?
Any help will be appreciated.
Thanks alot, I guess I'm too new to know!?!

Many people on this site say they do frig fondant covered cakes w/o problems.
Your use of cr ch filling definately means you need to frig this cake. A total of 4 hrs is all that filling can be at room temp - which includes the time you work on the cake and when it is 'on display' before being served.
Place the cake in a box, then into the frig. When you take it out do not lift the lid for at least one hour wich will allow any condensation to evaporate undisturbed.