Complex sentence: In 1814, prior to writing her famous novel, Mary was on a journey on the river Rhine and for a few hours she stayed at the town of Gernsheim, which is located about ten miles away from the castle.
Split into simpler sentences: In 1814, prior to writing her famous novel, Mary took a journey on the river Rhine. She stayed in the town of Gernsheim for a few hours, which is located about ten miles away from the castle.