The premier authority for information about John Alden and Priscilla Mullins is the "silver book" Mayflower Families Through Five Generations, Vol. 16, John Alden Family, compiled by Esther Littleford Woodworth-Barnes and edited by Alicia Crane Williams. Alicia is the genealogist of the Alden Kindred of America, Inc., and she has reprinted most of this information online at the AKA website http://www.alden.org. Another excellent source is The Great Migration Begins by Robert Charles Anderson. You can probably find these books at your library.