Wow- it is a big space!
Fridge boxes are very useful, as are the big "tubes" that carpet is rolled on, if you have a source.
I think rope lights could work, but you might want to see if some of your members have batterty operated camping lanterns that they might lend. That could look pretty cool!
You can hang tarps or paper "walls" using shower hooks and 3M hooks that release when you are done.
Can't wait to see the photos!
Jan