I had to access these bolts to remove door and hinges to replace worn hinges on a larger heavier coupe door.
If you remove the mudflap brace, the outboard end is connected to the fender with a large hex head sheet metal screw. You can then just pull the bottom edge of the fender away to gain access to the lower hinge bolts. I believe that the upper bolts are accessible without doing this, but it's easier if the car is up in the air. As stated prior, a box end wrench does the trick. I believe it's 1/2" or 9/16"
Admittedly, you just want to loosen them enough to adjust the door position, so you don't need to remove them. It's a process of trial and error - loosen, butch the door around, probably in closed position so the gap is even, tighten the bolts down and try opening and closing the door. then adjust it again.

Fender removal is not necessary to do this.