The fender is bolted to the firewall and the hood hinge. Loosen the bolts on the top and bottom of the fender next to the firewall. Also loosen the bolts that hold the hood hinge to the fender. Next loosen the fender mount bolt on the top and bottom of the core support. Some models also have a couple of small bolts that hold the splash pan to the frame, these will have to be removed and reinstalled after the fender is moved. You should now be able to pull the fender forward. You may also have to loosen the bumper support brackets to get enough clearance to move the fender, you should also prop the hood open with a stick or similar item to take tension off of the hood hinge to fender bolts. I assume that you are having clearance issues when you are trying to open the door. If so, this would be a good time to check the hinge pins on the door for excessive wear. Open the door about half way and lift up on the door handle or the bottom of the door.
If you can lift the door more than about 1/8 of an inch, you need new hinge pins, a common failure on these cars. Getting at the hinge pins is a major pain in the butt. To access the hinge pins, you will need to remove the front fender or the door. Depending on the amount of rust, removing the door might not be a good option as this can result in a lot of broken bolts that will have to be drilled out on the hinge mounts, another pain in the butt. Sometimes the mounts for the fender become bent and will need to be straightened. Usually that type of damage can be readily seen. Look at the fender on the other side to see if both sets of mounts look the same measuring as necessary. Replacement hinge pins and bushings still available. The hood is adjusted by loosing the top bolts on the hood hinge which is slotted.