My 1/2 quarter horse, 1/2 arabian was in a pasture for 2 years prior to my getting him 2 months ago. Now that he has other horses around him, and one really good buddy, Hunter, he gets very nervous when I ride or walk him too far away from the farm. He handles well in the arena and in the round pen. He is very well trained, except when we try to go for a longer ride away from the farm. Any ideas on how to curb this behavior would be greatly appreciated.