I have never had a need to refrigerate a decorated cake before. First time for everything. I have to deliver a cake on Fri AM.  I have somwthing very important health related on Thu all day. So i will be making and decorating most of the cake tomorrow.  Some of the fondant decorations i've already made, and they are easy to place on at the time of delivery. Buti have to paint some parts of the cake, not super-easy stuff, complicated enough that i will not have any time Friday to do it. 

If i paint it all tomorrow, will it do ok in the fridge? Will it do okay once out of the fridge?

Pardon such an amateur inquiry.

I have painted on fondant and gum paste with gel food coloring before on both refrigerated and frozen cakes. They turned out fine. There will be some condensation when you remove the cake from the fridge- the trick is not to touch the cake AT ALL until it evaporates and dries. Keeping it boxed while you bring it to room temp will help in the process.

Agreed with kitchen chick... And you can also box it, then have a fan blowing on the box, it helps to speed up the drying process as it gives through condensation, and keeps it cool at the same time