[HAULIN' IT]

You had said the bottom picture was "Before", so its hard for us to give good advice not knowing where things are now. Can you post up pictures of how it is now?
From that bottom picture you originally posted, you need to move the door WAY forward (at least on the top). Its hard to tell the rest due to not being in the picture, to be able to see how it fits the rocker, vertical at the quarter & roof.
If it fits all of the other areas ok then the door is the wrong shape...that upper front gap @ the windshield post simply isnt going to fly. The water would have to pour in as a result & if the back is good then the space for the window HAS to be too small. Twenty, Twenty Five years ago there was some REAL junky parts being sold for these trucks! $39 Fenders & $69 Doors...I remember it well.
As I said in my first post, the upper part of the fender doesnt look the correct shape from the top tip down to the chrome strip & the fender is back too far on the body.
One other thought I have is: "How is the Left side fitting?" Due to the curves in & out of the panel, if the front end (Rad support, frame, ect) is over to the Right, it will "pinch" the door gap since you are making a "V" viewed from the side.
Sure you can cut it to fit. With some skill & a welder its not all that hard BUT that should be quite a ways down on the list of things to do/check. My Two Cents, Lorne