The framing under the main deck and side deck won't show much, so I used some leftover Dura-Craft 3/16" x 1/4" strip wood to keep costs down.  The wood isn't nice enough to use for building or finishing anyway.

I started with the side deck since it requires the longest part of the framework.  I transferred the top boards to a work surface, this time keeping the back side facing up and lining up the ends using a T-square.  I used double sided tape again to keep everything in line.

I cut two long pieces and two short pieces of the Dura-Craft trim, gluing them to the flat boards and to each other at the corners.   I cut one additional long piece for the center of this box and glued it in place.  I had to use the glue sparingly so it wouldn't bleed through between the boards.  I left more leeway on the uneven side, which I'll explain in a moment.

But, when I lifted it off the tape, some of the boards separated.  :\

Ah, well, it wasn't a total loss.  I glued the boards back in place.  A good, solid assembly.  :]

As mentioned above, since one side had been aligned with the T-square, that left the other side uneven.  I marked the boards 3 3/8" across (down from the original 3 1/2").

I slid a piece of plywood under the edge and cut off the excess.

I repeated the process for the main deck, adding two inner lengths for support.  This time, after putting the double sided tape on my work surface, I tapped it with my fingers to reduce the hold it would have on the flat boards. I had only two boards come loose when I flipped the assembly over.

I also cut the boards down to 4 7/8" from their original 5" to align the uneven edge.  I will keep the two portions separate so there is no strain at the corner.

It's a clean fit.  :D

So far, it's working!  :D

There is enough of a gap under the door to require a step.

I think Cora likes it.