How long will a fondant covered sponge cake last?

[ScreamIfYouWantToGoFaster]

Hi - complete baking novice here. I'm hoping to make a fondant covered devil's food cake for my DD's naming ceremony. (I've been warned fondant is heavy and might crush the sponge, so I'll be doing a practice run first to see if I can roll out the fondant thin enough for the sponge to survive). My main concern is that ideally I need to make and decorate the cake two days before the ceremony. Will the sponge cake and frosting under the fondant last that long? I don't have a plastic cake container large enough :( so the cake would just be out on a table throughout that time (under a mesh to avoid flies of course).

Any tips? Is this a doomed endeavour?

Microwaves are airtight, you could store it in there if you've got one.

Not doomed at all.

Make sure that the fondant fully covers all of the cake and icing (no uncovered bits) and that creates a 'seal' around the sponge.

I've often made cakes too big for a plastic container or tin. Just make sure you store it in a cool room (out of subs glare and away from heat sources like radiators). I prefer to created a foil tent around the cake to protect it and effectively 'seal' it until needed.

Good luck.

Go faster, im making a cake tomorrow not to be eaten till sunday, be careful not to have the icing too thin though or you'll see lumps and bumps under the icing.