I am baking today and decorating tomorrow. I plan on crumb coating today, which I haven't done before, normally I crumb coat and decorate on the same day. I am trying to save time tomorrow. Do I saran wrap and crumb coated cake? Do I let it sit out and crust awhile and then saran wrap? I am very confused.
You know, when I do my crumb coat, I always follow it IMMEDIATELY with the final coat. I find that the second coat pulls up the crumb coat if it has had a chance to crust over.
Are you covering the cake in fondant the next day? If so, I bet it would be fine if you crumb coated, and then wrapped in plastic wrap.
JMHO! Lindsay 
i do a crumb coat the night before decorating all the time and let it sit as is....no problems so far
I am doing a three teir cake. Can I crumb coat and stack today and decorate tommorrow? My nerves are shot and this is my first wedding cake. There is filling and a sugar syrup to go on each layer, can I do these steps today and decorate tommorrow for delivery on Sunday? 
It shouldn't affect either one. It WILL give you some condensation on your frosting, though--most likely!
It's important that if you DO get condensation, just LET IT SIT and leave it alone--it will go away completely when the cake and the room are the same temp!
This is buttercream, right? Yeah...you'll be fine!
Good luck,
--Knox--
Just remember the crumb coat will be extra hard so more frosting will be required. I have done this one time but now prefer to put on the final frosting a few hours after the crumb coat. I hope you can get some sleep. I hate nights like that when I know what I could be doing and can't sleep. You will be fine. Be sure and post the image.
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