Okay, I moved the horse to the new barn yesterday. It went well, though it really could have been better.
The day started out rainy, which I didn't know until I walked out the door of my aunt's apartment. We got to the old barn about half an hour early to get all of my stuff in the car. Our driver pulled up with a tiny cattle trailer of all things and we all got yelled at (but little ol' me didn't have much trouble getting him IN the trailer).
The ride went smoothly and he was calm when we pulled into the new barn and unloaded. We put him straight into the new field (5+ acres from eyeballing it) and it took him 45 minutes to figure out that there were horses in his field, not only in the adjacent one. We left after he got to meet all the horses, and he'll be finding his place in the herd.
Already he's found a girlfriend, apparently a cute little black pinto.