I recently removed all the interior and insulated the cabin for noise and heat. I got the headliner out without removing the steering wheel. I removed the front seats and took it out the passenger side. It folded slightly, but popped right back into shape leaving no creases at all.
When putting it back in I did it the same way and it didn't fold at all.
Note: When replacing it I found that having someone to hold it up while i put those four plastic clip in the rear of it would have helped a lot as I kept having to fiddle with the clips using one hand while holding up the headliner with the other.
[EDIT] Also be careful with those clips, after many years they get brittle and tend to break. Dealer cost is 17 bucks each! (broke one)