Only Took Me Four Days...
It took me ten or so hours spread out over 4 days, and I really overdid it on my back and swore like you wouldn't believe, but I finally got up the subfloor in the hallway between the carriage house and the kitchen. The top layer was tile and that came up pretty easily, but the subfloor was glued AND nailed down with 3" nails, many of which were so soft they bent when I tried prying them up. My dad said I was milking it, but my inability to sleep because my back was so sore would suggest otherwise.
These floors and this room, we do not believe to be part of the original house. We think this part of the house was added on sometime later, likely in the 1900s. But whenever these floorboards were installed, and because they were under layers of tile and plywood, they're in pretty good condition. Our floor guys will sand them down and stain them to protect them as this is a high-traffic area. One door leads to the driveway, another to the carriage house which we're turning into the family room, and then there's going to be a doorway to the first floor bathroom. So these floors will get a lot of tread. I'm just really excited to see how they look.