Not exactly buddy sour... but need suggestions!

My 12 year old gelding does not like to ride out alone... yesterday he was so nervous he was spinning and throwing his head and would NOT go further than maybe 100 yards from the barn. ( I rarely ride alone.. so I can't say if this is new behavior or not..) Since I was alone, and not interested in getting thrown, he ended up winning that one.
So today I took him out on a lead line.. right past where he would NOT go yesterday. No problem at all.
It seems he is fine if he can see me - but once on his back, and out of his sight, he panics when he gets away from the barn.
So - I guess he is not really buddy sour.. not sure what to call it... but I am taking suggestions...

It has absolutely nothing to do with his being able to see you.

It has everything to do with him knowing you are in charge when you are on the ground and he knows that he is in charge and can make you get off when you are on him. Simple as that.

You are going to have to make him mind when you are on him or his behavior will get worse and worse with each battle that he wins. Very soon he will not do anything you want him to do while you are on his back.

Actually he is totally fine in a group, good in the round pen.. just not riding out alone...

If he'll do it when being led, but not from the saddle, he's putting you on. First and foremost, do not address this problem until you have all day to fix it. You cannot let him get the best of you, otherwise you're only training him to misbehave. I would first ride him back and forth to and from the barn within his comfort zone. Make sure you get just as energetic a walk away from the barn and you get toward it. Once that's good to go, start increasing the zone taking him a little further each time. The game is, he cannot turn back toward the barn until you say so, and even then, he can only come back in a calm state. If he's fussing and figiting, he's going to be walking around out there until he gives up his tantrum.

If your horse starts to act up when walking away, here's a few tips. If he tries to spin around and run home, do not let him complete the turn. Use alternating reins to turn him back in the direction you want to go. If you let him face the barn, he's already won. You don't have to ask him to go forward at that point, but he must stay facing where you want. Once he calms down (gives up) then ask for forward again.

If he plants his feet and refuses to move forward, try the drunken sailor walk. Using alternating reins, take a few steps to one side, a few to the other, etc. He's wobble down the path zig zag, but he'll be moving forward.

Increase your chances of success by rewarding him with a return to home whenever he relaxes outside of his comfort zone. If you absolutely have to, you can decrease how far you go just get the desired affect, but try to go a little further each time, even if it's only a few steps. Do not pet, pamper and baby talk to him. He's being a butt. He doesn't need reassurance, he needs leadership. He will respect yours as long as you are consistent and clear with what you want. Good luck!

He is quite simply barn sour.

He is fine a group because he is in his comfort zone with other horses.

He is fine in a round pen because it confines him and he accepts that.

What he is not fine with is you riding him without friends to a place that is beyond his comfort zone. When you are on him, he does not respect you enough to be obedient. He know he does not have to.

He simply knows when he is in charge. As time goes on, he will find more and more things to throw a fit about until he will do nothing you want.