Here are some photos of the process.
1 - Cutting out the center of the damaged floor boards so I can remove them individually.
2 - A clean opening.
3 - There were three damaged boards together, so I took them all out.
4 - Nailing in the replacement floor boards.
5 - Almost good as new. Just needs to be sanded, along with the rest of the floor, and poly'ed.
There are bigger gaps between some of the boards than I'd like, but I think it will all blend together a little when it's finished. I was a little bothered by them at first, but then I started noticing gaps between boards all over the floor, and I didn't want to show up the previous high-quality workmanship.