How can I access XMLSitemap links from external PHP script? I have an external PHP script that does a lot of back end processing for a website.  I need for this PHP script to query, insert, and delete various links from the XML Sitemap.

I want to use XMLSitemap's API instead of raw SQL so any additional functionality that needs to happen on inserts and deletes are called, like any alter hooks, etc.

I don't want to bog down the website for this processing, hence why I need to do this from a back-end script.
You'll need to bootstrap the Drupal environment in your PHP script to do this. There are many ways to do this, probably the easiest is Drush's php-script command:

drush php-script my_custom_script.php


This will let you execute any arbitrary PHP script in a bootstrapped Drupal environment.

Once you have your script running your Drupal environment, you can utilize the XMLSitemap API functions for all your CRUD operations.