JH,
Is the roof already framed? If not place 2×4 roof
rafters 2ft. on center, cover the roof with 1/2 inch
plywood, place 15lb. tar paper, and finish off
with an inexpensive 3 tab roof shingle. Figure
on a solid 6-8 hrs to do it by yourself. Just
the roof should work should take 2 hrs. For that
drawer why not try epoxy in the joints.