Ours wasn't a Mickey theme, but DH and I did bumblebees, and it was pretty easy. We found a costume at a costume store that was a vest thing, yellow and black striped, with the wings attached. We wore black long sleeve t-shirts, balcks shorts, black stockings, and little antennae. It was all pretty easy to pack, laid pretty flat and didn't take up a lot of room.
We found the bee vest things at Spencers Gift store in our local mall.