Used to trail riding alone
What I would do is start by ponying the younger horse with a older, steadier horse that is good on the trail by itself, no problem. That way, he can get used to being on the trail and have the confidence of the buddy system being right there. Really build a strong relationship with him by doing ground work, grooming, feeding, ect. This can help when it comes to backing him and so on later on in the future.
And, if you don't have any confidence, the horse wont have any confidence. Start going out on the trail with friends and their horses at the barn where you are at so you can get used to being on the trail. When you are alone, the horse looks to you as a leader. They need to be able to trust you. But when you are just as nervous as the horse, that does no good. Hope this helps, keep us updated on your progress!
Shaneequah, 1998 gaited Bashkir CurlyxArab mare
Johnny Cash, 2001 Arab x pony gelding
Brighty, 2013 Standard Donkey jack