I love love love these plans! Based on the helpful comments made by other readers, I decided to narrow the bed by leaving one 1x3 out of the head and foot board panels and shortening the other 1x3's and 1x2's as needed. Added mitered trim around the head and foot boards.
The build was super easy and only took a couple of hours. I'm classifying this as a "day project" (6-9 hours) to allow time to paint or stain.