William traveled with a company of non-Mormon Iowans who were headed toward California in 1852 . The party stopped at Salt Lake city for the winter; while here some members the Cooke family converted to the faith.
Documentation indicates that the family traveled to Utah in 1852. However, they appear in the 1850 Federal Census of Utah. Further research is needed to determine if they made two trips to Utah or if there is an error in the documents.