Change the 'Read More...' links in WP core & Genesis; Post columns grid patterns to allow 2 - 6 grid columns.

post.php

<?php
namespace albemishpc\post;

/**
 *  Post structure handling.
 *
 * @package    Utility Pro\post
 *
 * @since      1.0.0
 *
 * @author     Robert A. Gadon
 *
 * @link       http://spiralwebdb.com
 *
 * @license    GNU General Public License 2.0+
 */

add_filter( 'the_content_more_link', __NAMESPACE__ . '\change_the_read_more_link' );
add_filter( 'get_the_content_more_link', __NAMESPACE__ . '\change_the_read_more_link' );
/**
 * Change the default 'Read More...' link HTML markup and content.
 *
 * @since 1.0.0
 *
 * @param string $html
 *
 * @return string
 */
function change_the_read_more_link( $html ) {

	$html = change_read_more_text( $html, __( 'Continue reading', 'utility-pro' ) );

	if ( doing_filter( 'get_the_content_more_link' ) ) {
		$html = strip_off_read_more_opening_dots( $html );
		return '</p><p>' . $html;
	}

	return sprintf( '<p>%s</p>', $html );
}

/**
 * Strips off the read more link's opening dot pattern.
 *
 * @since 1.0.0
 *
 * @param string $html
 * @param string $dots Dots pattern to strip off
 *
 * @return string
 */
function strip_off_read_more_opening_dots( $html, $dots = '&#x02026; ' ) {
	return substr( $html, strlen( $dots ) );
}

/**
 * Replace the read more text from the Genesis default text of '[Read more...]' to
 * the new specified replacement text.
 *
 * @since 1.0.0
 *
 * @param string $html Read more link HTML
 * @param string $replacement_text Replacement text
 *
 * @return string
 */
function change_read_more_text( $html, $replacement_text ) {
	$text_to_replace = __( '[Read more...]', 'utility-pro' );

	return str_replace( $text_to_replace, $replacement_text, $html );
}


add_filter( 'post_class', __NAMESPACE__ . '\add_to_post_classes_for_grid_pattern' );
/**
 * Add Attributes to the Post class
 *
 * @since 1.0.0
 *
 * @param array     $classes    An Array of post classes.
 * @return array    $classes    An Array of post classes.
 */
function add_to_post_classes_for_grid_pattern( array $classes ) {

	if ( ! is_array( $classes ) )   {
		return $classes;
	}

	if ( ! is_home() ) {
		return $classes;
	}
	// Default $number_of_columns = 2.
	// Pass an integer from 2 - 6 along with $classes to specify number_of_columns.
	return get_classes_for_grid_pattern( $classes, 2 );
}

/**
 * Based on the number of columns requested, get the styling classes for the grid pattern.
 *
 * @since 1.0.0
 *
 * @param   array   $classes                Post classes.
 * @param   int     $number_of_classes      Number of columns to set for this grid pattern.
 *
 * @return  array
 */
function get_classes_for_grid_pattern( array $classes, $number_of_columns = 2 )    {

	if ( $number_of_columns < 2 || $number_of_columns > 6 ) {
		return $classes;
	}

	// Call the global instance of the WP_Query object to interact with the $current_post method below.
	global $wp_query;

	// The index position with the array equals $number_of_columns.
	$column_classes = array(
		'',              // index 0
		'',              // index 1
		'one-half',      // index 2 = represents 2 columns
		'one-third',     // index 3
		'one-fourth',    // index 4
		'one-fifth',     // index 5
		'one-sixth',     // index 6
	);

	// Copy the column class out of the array above, and add it to the end of the $classes array.
	if ( is_post_of_post_type() )  {
		$classes[] = $column_classes[ $number_of_columns ];
	}

	// Add the 'first' styling class to $classes[] when the modulus remainder == 0.
	if ( $wp_query->current_post % $number_of_columns == 0 ) {
		$classes[] = 'first';
	}

	return $classes;

}

/**
 * Checks if the current (or specified) post is of the specified post type.
 *
 * @since 1.0.0
 *
 * @param string            $post_type
 * @param int|WP_Post|null $post_or_post_id     Post ID or post object. When `null`,
 *                          WordPress uses global $post.
 *
 * @see get_post_type()     Retrieve the post type of the current post or of a given post.
 *
 * @return bool
 */
function is_post_of_post_type( $post_type = 'post', $post_or_post_id = null ) {
	return get_post_type( $post_or_post_id ) == $post_type;
}

Per Tonya Mork (@hellofromtonya), make the following changes:

1. Avoid use of the global $post variable in the get_classes_for_grid_pattern() callback. The global variable can be overwritten, and consequently affect the entire behavior of a site in unintended ways.
2. As an alternative, use the WordPress API by using the function get_post_type(). By default, this function returns the global $post object when the parameter is set to $post = null.
3. Create a helper function is_post_of_post_type() that accepts the type of post type you wish to check, and then pass in the get_post_type() function, and return the callback as a conditional that checks for a boolean value. Use the helper function in get_classes_for_grid_pattern() with a conditional statement to target the use of the desired post_type.

Add code to change the Read More... links in WordPress core and Genesis.