I used something my friend refers to as masonite, but at Home Depot they just call it "hardboard". It's really not that hard, though. It's like peg board without the pegs in it. It bends pretty well and it's sturdy at 1/8". That stuff isn't going ANYWHERE.
The whole thing will be detacheable to get through doorways. I used carriage bolts to mount it. Breaking it down would probably take 10 minutes, though, because the top and bottom portions of the CP aren't connected to each other. They each attatch seperately to the cabinet. When the CP is closed it screws down in a several spots, but in an open position the 2 halves aren't connected. Does that make any sense?