Complex sentence: Historian Bradley F. Smith of the Hoover Institution speculates Maria may have moved to a city and taken a job as a housekeeper, or stayed in her home village of Strones and found casual employment.
Split into simpler sentences: Historian Bradley F. Smith of the Hoover Institution speculates that it was possible Maria went off to a city and took a job as a maid. He also states that on the other hand, it was possible she stayed in her home village of Strones and found casual employment.