I doubled up a rafter on my lean-to and wrapped a chain around it. This worked really good at both unhooking it and hooking it back up again. The only thing I didn't like it it took up the entire front of one of my storage bays. Because of the ROPS, I couldn't back in all the way, so I had to leave the post hole digger near the front and middle of the bay. This took up a HUGE amount of space.
I sold that property and don't have the same setup at my new place. For now, I'm drilling it into the ground and leaving it there. It's still easy to hook up, but in time I'm gonna have issues with rust. So far it's been over a year and no sign of rust yet.
One of my up and coming projects will be to build a storage shed. I'm going to use a 6x6 post for one of the posts and build a metal bracket that will swing out and back onto the side of the post. It will only stick out four feet, but then rotate back into the shed. I'm going to hang my post hole digger from this bracket. This way I can have plenty of room to attach or take off the post hole digger, but then I can swing it into the shed behind the post so it wont be in the way.
Eddie