I have been in the process of replacing (or trying to at least) all the body bolts/cushions...however, when I went to remove the old bolts in the rear, (behind the rear wheel) the bolt kept turning as it seems the nut (up behind the body support reinforced location) became loose.  As you know there is no access location as there is on the second body bolt location (in front of the rear wheel).

Question is...can anyone give me some ideas on how I can remove the old bolts given the current situation?
Thanks in advance.