I suggest doing it the professional way, the way you would transport it for decorating competitions.
1) Bake the cake layers and then freeze them very solid. Wrap them carefully in plastic wrap.
2) Pack each layer in a separate box that has been lined with a solid cushioning material, like foam (but not anything chunky such as peanuts, in case you get a delay and your layers defrost.)
3) Tie the boxes shut but do not tape them. You might be asked by TSA to open the boxes if the cake layers turn out to look dense on the xrays. Carry on the cake layers, because they are delicate, even frozen.
4) Also get your icing very cold. Pack it in a sealed pastry bag with room for air expansion, then inside a second ziploc, and pack it in a container with styrofoam or similar insulating material so that it won't get really hot in the hold. (You cannot use ice or dry ice in checked baggage.) Put the icing and your decorating tools in your checked baggage (because you wouldn't be able to take the tools in a carryon, anyway.) Mark the outside of the container to explain that the content is cake icing -- it is pretty much guaranteed to be inspected, because it will look suspiciously like plastic explosive material.
Then when you get to your hotel you will be able to ice the cake with your tools. You might want to also pack the final-size box flat in your checked luggage so that you will have a container to deliver it in. Don't forget tape.
As for sugar art, I really wouldn't bother. It is hellishly difficult to use in central Florida humidity, and pieces made elsewhere will nearly always soften before you can manage to serve them. (You'll notice whenever you see solid decor pieces on Disney's specialty desserts, they will be frozen solid; it is the only reliable way to keep them from drooping.)