If you added another door to the long side near the run then you would be able to reach better.
You could clean what you could reach from the existing door, then get the rest of it from the new door.
Is it on the end or the side?
You might be able to add another access door to the one it's not on so that you can more easily reach all areas of the coop with your manure fork.
These coops are that wide but not full-height, walk-in models? That's extremely awkward.
You should probably consider modifying your coops to make cleaning and maintenance easier. Can you create new, larger access doors to allow you to reach into the coop more readily? Maybe putting doors...