I used an electric sander on as much of the piece as possible, and sanded the hard-to-reach parts by hand. Above is the piece after all of the sanding was complete.
Here is when the progress starts to show. It never ceases to amaze me what a difference primer makes.
It has taken me a while to realize that this piece is never going to be perfect, it has imperfections that cannot be sanded, or painted over. I'm learning to be okay with this. I have a long history of being incredibly critical of my own work/projects. It's something that I'm always working on, and I'm hoping to pick up a couple of valuable lessons while completing this less-than-perfect piece.