It appears that James Murdock married Elizabeth (Kerns) Collins in 1845, about 3 mos. after the death of his first wife, Susannah Akers.It looks as though the two youngest of his children with Susannah would have been still with him when he married Elizabeth:Eliza (1828-1919) and Rebecca, b.1832.
In his will he mentions 2 stepchildren (Elizabeth's children by her first marriage): Catherine (Collins) Callahan and Abner Collins.He and Elizabeth had at least two children together: Frances and Dora Isabel.
James and Susannah Murdock were living in Highland Co. when she died, and that is where he married Elizabeth.By 1850, they turn up in Logan Co.Rebecca Murdock, my gr-gr-grandmother,married Calvin Marmon in Logan Co. in Jan. 1850, so she obviously moved to Logan Co. with her father and stepmother.
If you want to email me at firstname.lastname@example.org, I can put you in touch with a direct descendant of Dora Isabel Murdock, who gave me much of my information.