You have to remove the outer fender skin, it's the ONLY way.
Loosen the header panel and unscrew all the bolts around the door jamb and at the top of the fender.
I did this for my 86 long ago, it's not as hard as you think, you only need a 10mm socket and a 1/4 drive ratchet with a few long extensions for the header panel bolts at the front of the fender.
You have to loosen the header on both sides and at the top of the core support so as not to crack it and just scoot it out a little so the fender skin can come up and out.
There is also a little 7mm bolt at the base of the front of the fender that attaches to the wheel well as well as the reflector.