FIRST: This only works when you own wintergrasp, so if you need to go out for a snack and love leaving your toon logged in like me, park him here.
http://img11.imageshack.us/img11/2499/noideab.jpg
Put your toon in this spot (might work for anywhere inside the keep)
Somehow when you go afk automatically, you come back from AFK almost instantly.
I have no idea why this works.. but I tested it for an hour without touching my mouse/keyboard/or use any program.