User blog comment:MarkvA/Skyrim's Most Wanted Features and Fixes/@comment-68.8.177.52-20111130222937/@comment-78.53.91.125-20111130231839

Pick the lock on the gate and once inside the yard use a horse to jump into the tree all the way to the left again and again. You'll be "climbing" that tree on your horse and eventually jump over the wall.