You could also try ponying him with another horse that is calm and easy going. I use ponying to get green broke horses out on the trail. Makes a huge diffrence.
I will pony a horse on the trails for a week or two then have someone else ride pony horse ,and I ride the horse id been ponying. Usally the first ride out after horse spent a week or two being ponyed is a calm event.
They go down the trail with no problem because they been there done that being ponyed.