In chronological order of setting, my choices are:
Here be Dragons - Sharon Penman (12th century)
Katherine - Anya Seton (14th century)
The Three Musketeers - Alexandre Dumas (17th century; overlap with Eponymous Challenge)
Joseph Andrews - Henry Fielding (18th century)
Pride and Prejudice - Jane Austen (19th century)
Cocaine Blues - Kerry Greenwood (20th century; overlap with 888 Challenge)
Now I just have to wait until 1 April to start!