I love doing home museum tours because I have always found them fascinating in a way; it's a great way to see inside of a person's life, and get a sense of the time period of which they lived in so I was pretty excited to see the Campbell House listed as a participate of the "Open Doors" while I visited Toronto.
Overall this was a perfectly fine hose to explore. I'm not sure if only certain rooms were closed off merely for Open Doors if things are always shut off but I only had access to certain rooms and there wasn't much in each room. There wasn't a guided tour so I kind of wondered aimlessly through two rooms on the first floor and the two on the second floor.
That's not saying that the house isn't beautiful or that I didn't learn anything, I just didn't learn much. Since it was free during that weekend I didn't mind it, but don't think I'd run back again to do another walk through. I do think it's fascinating that they moved this home from one location to another, but don't know why they would put it next to a subway station on a busy street.
If you're looking for a short amount of time to kill (maybe 30 minutes) then check it out, but there are plenty more interesting sites in Toronto of historical nature that I'd go to first.