I took a few days off from the project (fishing, errands, shopping, TV) but got back to it yesterday. It was "glue and screw" time. I took the time to very carefully align all the corners square and flush.
Since I was using mostly 1 x 4" boards and had many places where I was screwing through the wide edge into endgrain, I made a small drilling jig. Nothing fancy, just a piece of scrap from 1 board. I drilled pilot holes centered halfway of the thickness and set 3/4" from the ends. You can see it in the 1st picture (where I was using it as a clamping block). It really made it easy to drill pilot holes evenly spaced, straight, and right in the center of the boards.
I did half of the basic frame yesterday and let it dry overnight, using a framing square to keep it, well, "square".
Today, I glued and screwed the other half, plus attached the 2 cross braces. When that was done, I prepared to cut (to fit) and attach the 2 vertical braces.
OOPS! I had estimated the 2 pieces to be 23" (and had a 46 1/2" board for the purpose. Guess what? The space to be braced was actually 23 1/2" on each side. I was 1/2" short. I HATE "nominal sizes"! Why can't a 1 x 4" board actually be 1 x 4"?
Fortunately, with all the corners being connected in 3 directions, and glued and screwed on all the edges, it was solid as a rock. So here it is, ready to be polyurathaned tomorrow.
I'll post the "finished" picture when the polyurathane is dry and I have the rack in place with the rods on it...