Life got in the way, but I'm back.
My husband's schedule has been crazy. Both of us were home and got the skid steer going. Still going to have big weed problems. We dumped a load of really nice loose top soil there years ago, plenty of good soil to work with.
Thanks for all your suggestions.
Attached are new photos, taken early morning. You can finally see the size and shape. There is a 4 foot fence post for scale.