Complex sentence: He commandeered a desk in the anteroom to the editor's office, a location that kept him closely in touch with the daily affairs of the paper and gave him ready access to the editor, William Rees Mogg, with whom he developed a good friendship.
Split into simpler sentences: He commandeered a desk in the anteroom to the editor's office, a location that kept him closely in touch with the daily affairs of the paper. It also gave him ready access to the editor, William Rees Mogg, with whom he developed a good friendship.