I need to make a cake for a party that is on a Sunday. I would like to make it on Friday and use a crusting buttercream. I usually cover cakes in fondant and theyre ok left out or in my garage (because its colder in there) for a few days, but will a cake covered in crusting buttercream be ok left out for a few days? Or should I refrigerate it? Its also going to have fondant decorations on it. Thanks so much for the help!

Yes, it'll be fine left out at room temperature as long as perishable fillings aren't used.

Thank you for your quick reply!!