I finished The Duchess. I thought I had about 50 pages left to go, but it turns out that I had about half that because the end bit was actually just a preview for one of her other books. As expected, half the people and events didn't matter at all! It could have been pretty good, but as is it was mediocre.
Here's a full summary spoiler for anyone who's interested:
Spoiler
A duke has a son and a daughter. The son is kind of a turd, and the duke is much closer with the daughter, but he has to leave everything to the son. But he's able to sneak some money to the daughter right before he dies. Since the son owns everything, he kicks the daughter out of the house right away and tells her to go live with his friends and be their nanny. She works there for a year and a half, and it goes very well. But then one of the people's drunken friends tries to rape her. She's able to fight him off, but he's angry. So he tells the people that she tried to seduce him. They say they don't want a whore taking care of their kids, so they fire her. She then dips into the money from her father to get a hotel room. She then finds a prostitute who has been beaten and left in a gutter. She brings the prostitute back to her room to clean up and heal. The prostitute tells her that there are a lot of pimps and madams, but they abuse the girls and hardly give them any money. So the daughter decides to use some of her father's money to buy a house and to be a better madam, and she invites the girl and her friends to live and work in her house. So that goes very well for a year and a half. Then one of the men shoots and kills another man at the brothel. So the daughter decides to go far away for a while to let things cool off to avoid a scandal. While away, she met a man, got married, and had a son. Her husband died in an accident a few years later. Between her father's money, her brothel money, and her dead husband's money, she was very rich. Her brother, on the other hand, had gambled all his money away and was selling their family home. So she bought it, and her son will be the next duke when the brother dies because the brother never had any sons. The end. But then throw in lots of descriptions of clothes, the same things being repeated many times, tons of descriptions of how she's so beautiful and everyone loves her so much, lots of extra characters who make no difference at all, etc