Not that it is a huge problem to get to anyway, but I took some time to make accessing the water pump easier on my 287bhss.
The pump is located in the pass-through on the street side, and being a larger guy who has trouble climbing inside to get to the screws to remove the panel, I decided to simplify the amount of time I have to spend as a sardine.
I carefully removed the trim piece seen on the left of the first picture. It was originally attached to the stationary middle panel so that the removable panel had to slide behind it. I reattached it to the removable panel just so the trim piece would cover the gap. Then I took a piece of PVC molding and cut it to reveal a thumb-screw sort of retainer, that can rotate. Then I glued a piece of 1/2" square stock just inside of the hatch opening on the right hand side to hold that end of the panel in place. So the panel slides into the small gap between the hatch door frame and the existing frame and stays put without screws. Then the other end pushes back into place, and the thumb screw holds that end in. Tool-less removable/replaceable in seconds, and no more trying to get in there with a screwdriver to remove it.
REMOVABLE PANEL WITH PASSTHROUGH DRAWER PUSHED OUT OF THE WAY - 1/2" stock piece is glued between the frame and the panel on the far right of this picture out of view):
THUMBSCREW IN "LOCKED" POSITION
THUMBSCREW IN UNLOCKED POSITION
PANEL REMOVED AND SLID OUT OF WAY