How to remove side mirrors on 2000 Airstream Land Yacht

On my previous coach they just unbolted from the outside. It would appear that on this one the outer screward attached to backing nuts hidden behind interior panels. This is a critical issue for me because I need to remove them in order to fit in my bay adjacent to my house. First I need to get them off then figure a way to remove them from the outside, like a plate with stud bolts perhaps.