AI am an avid baker but I have never been in this situation before. I am making a three tier birthday cake for a surprise party, but have to leave the day before the party. The cake will have to sit out decorated. Where's the best place to put it to keep the fondant and decorations from getting gross? Also, after making the cake part, what do I do with them? I'm making the cake one say then the next frosting and decorating all of it. I've heard freeze the cakes, plastic wrap, tea towels. Help please!

For storing the undecorated cakes, after they've cooled, I wrap them in plastic wrap and stick them in the freezer.  Take them out a couple of hours before decorating (longer if they are a dense cake like a pound cake - those take forever to thaw!)  I usually do any torting/trimming on the second day, just before icing.

I quite often finish my cakes the evening before they are needed, for fondant cakes I normally leave them on the counter out of direct sunlight, with a cardboard box over them.  

Good luck!  Post pictures when you're done! :)