pariahdecss

Ultimately I was able to do this by adding the following to functions.php

/*———————————————————————————–*/
/* Order Admin Pages by Date by Default
/*———————————————————————————–*/

function set_post_order_in_admin( $wp_query ) {
global $pagenow;
  if ( is_admin() && 'edit.php' == $pagenow && !isset($_GET['orderby'])) {
    $wp_query->set( 'orderby', 'date' );
    $wp_query->set( 'order', 'DSC' );
  }
}
add_filter('pre_get_posts', 'set_post_order_in_admin' );