I changed a few things in the plans. First of all, I used pre-cut pine project boards I got from Lowes. I had to cut them length down of course, but the width was 16". Therefore, the cut list did change. I also just installed the baseboard as one would normally. I didn't want to do the cut-out and have it supporting the structure. We also mitered the baseboards and the cove molding. It didn't say in the plans how to attach the moldings, so we used 3/4" brads on the cove molding and at the top of the baseboard. We also used the 1 1/4" brads at the bottom of the baseboards. Other than that, we followed the plans and it turned out great! I used the Minwax Express Color in Indigo...and I love it. I managed to use just 1 tube on the entire piece (minus the bottom)...I had to do some minor surgery to the tube to get more out....but nonetheless, I did it! I also put some felt pads on the bottom so the floors wouldn't get scratched...which is why it sits off the floor a little bit.
We chose to use the solid pine project boards to make sure it lasts for as long as we keep it around. We didn't use any plywood on the project at all. It is 100% solid wood.