Here is the near finished trunk. 

-A friend cut a chunk out of a white hood from his body shop. 
-I cut the hood into a square piece that fit in the trunk area
-I welded the metal to the frame rails
-I layed several lines of silicone sealer inside the trunk seam and underneath the car along the weld seams
-I sprayed the underbody with rust preventing gray primer
-I sprayed the underbody with rubberized rust/sound deadener.
-I sprayed the gray primer inside the trunk
-I will follow up with spraying white spray paint over the primer
-I will use a drill step bit to open the holes for the rear differential access bolts as well as the old windshield nozzle holes to 3/4” or 1”
-I will buy a few electrical box plastic plugs and pop them in the remaining holes.
 

Good as a factory trunk minus the space for a spare!