Shaun,

If you haven't started to take the barn down already, take plenty of pictures both before and as you take it down. Take a few of the barn and the surrounding area.

No matter how well and carefully you put it back together, it will never regain its historical cultural landscape. Barns once moved from their original site loose some of their cultural message. However a two dimensional record is better than none.

Please do not misunderstand me. If moving a barn is the only way to save it, then it is the correct thing to do. Just record them before they get moved.

Best of luck with your endeavor.
Rolland