I don't think this is going to be easy. If its like my car you might be able to remove the inside kick panels and then look to see if you can cut a window in the sheet metal to get to the bottom hinge bolts. To make matters worse you may be dealing with caged nuts so there may be remnants of the cage blocking access to the nuts. The nuts are probably square so a regular socked won't work either. There are sockets available that work with square nuts. Otherwise you may have to cut a decent sized opening to get a set of vice grips onto the nuts. It also looks like the corner part of the dash would have to be removed to even see if you can do the same with the top hinge. Hopefully the top nut of the upper hinge is not one of the ones that has broken loose as I fear it would be the most difficult. Alternatively I wonder if removing the fenders might give you access to the back of the hinge. You would want to find out for sure before attempting that. Barring this there is always the hope that someone else knows a special trick. Good luck.