FYI
i was able to provide zen-cart with access to the WP libraries by copying this line from the wp index.cfm
require(‘./wp-blog-header.php’);
and adding it to the zen-cart index.cfm, and changing the relative path to reference the higher directory
require(‘../wp-blog-header.php’);
Note: do not add
define(‘WP_USE_THEMES’, true);
doesn’t stop the functionality but did some weird stuff with my styles/themes