The sides and ends needed to have dados to accept the top and bottom. So as not to have the dados extend through the pins, stopped dados would do the trick. These were made on the router table. 1/4" wide and 5/16" deep.
It was time for a little finessing of the joints to assure everything fit.
Yes, there it was staring me right in the face! How could I not see what I did. Worse yet, how am I going to fix it now?!?!?!?
I picked up the test piece and it finally hit me! If I cut the top completely free, there will only be one pin for the lid "tail". There will be no structural element (second pin) to hold them together. Even the best glue won't hack it here. Hmmm... can't weld wood together. Maybe a glue block on the inside corners. There's not much material between the top and the edge of the lid.
At this point I stopped and went for a long walk. Several thoughts went through my mind- including selling all my tools and just sitting on the porch watching cars go by. But then it came to me-
After assembling the box, I could drill a hole in each corner. The depth of the hole would be just shy of the saw kerf. Gluing a dowel into the hole should provide enough strength to make the joint stable.
Next time- making the top and bottom.