Multiple categories rewrite rules in WordPress. Example: /cat/child-cat/grandchild-cat/cpt-name/

your-plugin-main-file.php

<?php
class Your_Plugin {
  /**
	 * Post Type slug modification
	 *
	 * @since 1.0.0
	 * @return null
	 */
	function modifySlug($link, $post)
	{
	    if ($post->post_type != $this->hotel->getUniqueID())
	        return $link;

	    if ($cats = get_the_terms($post->ID, 'destinations'))
	        $link = str_replace('%destinations%', $this->getTaxonomyParents(array_pop($cats)->term_id, 'taxonomy_name', false, '/', true), $link);
	    return $link;
	}

	/**
	 * Chaining the taxonomies hierarchy
	 *
	 * @since 1.0.0
	 * @return null
	 */
	function getTaxonomyPath($id, $taxonomy,$tree=array(),$index=999)
	{		
	    $node = &get_term($id, $taxonomy);	    

	    if (is_wp_error($node)) {
	        return $node;
	    }
	   
	    $tree[$index] = $node->slug;
	   
	    if ($node->parent and ($node->parent != $node->term_id))	          
	        return $this->getTaxonomyPath($node->parent, $taxonomy, $tree, --$index);	       
	  	ksort($tree);
	    return implode("/", $tree);    
	}
	
	/**
	 * Add hooks and filters
	 *
	 * @since 1.0.0
	 * @return null
	 */
	public function hooks() {
		add_filter( 'post_type_link', array($this,'modifySlug'), 10, 2);
		add_filter( 'rewrite_rules_array', array($this,'modifyRewriteRules'),10,2);
	}
}