Neubob, I can help.
1. First thing, modify your windvane so it accurately reflects the current wind-direction. The first rule of warfare is deception, and he's operating under the assumption that the windvane is off, so by making it work properly, you will defeat any plans he might employ that require knowledge of winds.
2. Let him park in The Spot, but whenever his car isn't there, stealthily add to the oil stain so he begins to suspect mechanical failure. His own uncertainty will grow to be his biggest enemy.
3. When he replaced your mailbox with the trash can from the local chinese restaurant, he had an important victory. Effective retaliation must, by it's very nature, be overwhelming. To wit, you must do the same to his mailbox, but with a trash can from a different restaurant that is _much further_ away. The unmistakable menace of waking up to a trash can from a shop two blocks down the street can't be shaken off easily, and, in combination with #1 and #2, your maskirovka will be complete.
