It took me years and baby steps to do it, but I can get my horse out alone without too much fuss depending on the season and his mood on that given day. If he's in a confident mood, we brave the trails in the woods. He's not too great with wildlife. He's getting better with the wild turkeys, but deer, not so much. When he gets sticky, I sit there and keep him pointed in the direction I want to go until he realizes that I am more stubborn than him and we're on our way. For bigger spooks, deer and other wildlife, it's usually a combo spook/spin/bolt attempt. One rein stop has saved my butt a zillion times. We have the move down so well, he can only spook and get half way through the spin before I've shut him down.
On days that he's more "up", we stay in the nearby fields where he can still see the barn. Once we've been running around for awhile and his brain has switched over to fun mode, we usually do a short loop into the woods to build on his confidence. I always tell him he's a big brave stud on the way home and he becomes very proud of himself and blows out a nice relaxing "I'm a good boy, I did it mom".
My only gripe is, this is a lather/rinse/repeat process. Every spring we start anew as if he's never seen so much as a squirrel. By September he's blowing through the woods like the destroyer. Hacking out alone is...um fun...yeah that's it...fun.
You just have to see your distance...you don't have to like it.