Walking calmly past the scary garbage can and wheel barrows. This is a very different horse than the one that hates going near those under saddle. I think it's all about
finding what the horse is comfortable doing for his job. I'm sure he won't love driven dressage, but that's different than the tension he tends to have under saddle. I take my horses to a variety of places, and without the consistency of working in the same ring every day, he made it clear that taking him out in harness would make him a much happier pony.