This morning I finished sanding the entire guitar again with 220, then filled the grain of the back, sides, and neck with dark Timbermate filler. After the filler dried, I sanded the entire guitar some again.
After the guitar was completely sanded, I roughed out a bone nut and glued it in place, then masked off the fingerboard and bridge location. I filled the soundhole with towel and paper, and here's the guitar all ready for finishing!!!