As you can see the replacement skin worked out. They decided the best way to seal everything up was to glue the skin and tac weld several places along the seam.

from what I see the new skin looks "swiss cheesy" in the front corners too. Ive been looking for another D/W truck myself. my son has 3, and his 90 has the biggest issues with the roof. He has fiberglassed his a couple times and has had to strip it and redo it as the "cancer" has gown. He does have a better cab that he can swap onto that frame, it needs some work 1st though. like cutting out the tranny hump and putting in the big 4X$/manual trans one.... Im surprised that even southern trucks had that issue?
Up here in the north I have mostly seen cab mount structure rotting out, that 45* part that extends from the rocker inward towards the frame, I have had to rebuild a few of those over the years. have seen more and more top-rot issues as the years have gone by though. Around here it seems that as the D/W series trucks got "newer" the last few years of that series of trucks are the worst for top-rot (my name for the skin and rain gutter rot out issue) and rocker panels. seems the 70s and earlier 80s ones are still holding up better than 'ate 80s til the end of the D/W in 93...

oh I have done my share of floor pans in them....

currently looking for another D/W myself, should have never sold my 83 which was my last of that series of trucks (but not the newest of them I have owned)
looking on CL from TX to AL to GA and FL at the moment.... hoping to avoid having to do "too much" bodywork, mechanicals don't bother me as bad....
my son just had an 80 slant 6 stepside shipped here from Mississippi that he got off of EPay. wish I had the money he does to "play around"....

Looks like someone owned stock in Vise-Grip! That will make a proper repair.