Use this grid loop in a custom page template to show page content, followed by a loop through a custom post type.

archive-testimonials-grid.php

<?php

/**
 * Template Name: Testimonial Archives
 * Description: Used as a page template to show page contents, followed by a loop through a CPT archive  
 */

remove_action ('genesis_loop', 'genesis_do_loop'); // Remove the standard loop
add_action( 'genesis_loop', 'custom_do_grid_loop' ); // Add custom loop

function custom_do_grid_loop() {  
		
	// Intro Text (from page content)
	echo '<div class="page hentry entry">';
	echo '<h1 class="entry-title">'. get_the_title() .'</h1>';
	echo '<div class="entry-content">' . get_the_content() ;

	$args = array(
		'post_type' => 'testimonials', // enter your custom post type
		'posts_per_page'=> '12',  // overrides posts per page in theme settings
	);
	$loop = new WP_Query( $args );
	if( $loop->have_posts() ):
		echo '<div class="grid-loop">';
		while( $loop->have_posts() ): $loop->the_post(); global $post;

			$classes = 0 == $loop->current_post || 0 == $loop->current_post % 2 ? 'one-half first' : 'one-half';
			echo '<div class="' . $classes . '">';
			echo '<h4>'.genesis_get_custom_field( '_cd_client_name' ).'</h4>'; //retrieving a custom field from the post
			echo '<strong>' . get_the_title() . '</strong>';
			echo the_post_thumbnail( 'thumbnail', array('class' => 'alignleft') );
			echo '<blockquote>' . get_the_content() . '</blockquote>';	
			echo '</div>';
		
		endwhile;
		echo '</div>';	
	endif;


	// Outro Text (hard coded)
	echo '<div class="call-to-action">This is my call to action text. <a href"">Contact Me</a></div>';
	echo '</div><!-- end .entry-content -->';
	echo '</div><!-- end .page .hentry .entry -->';

}

/** Remove Post Info */
remove_action('genesis_before_post_content','genesis_post_info');
remove_action('genesis_after_post_content','genesis_post_meta');
 
genesis();