Show a WP page outside of WP?

I’ve looked online for this, but can’t quite find what I’m after.

I want to be able to show the content of WordPress pages outside of WordPress itself, including any shortcodes, and possibly sidebars but that’s not as important. I don’t need the header or footer.

Why would I want to do this when WordPress can do anything you want it to do?

I’m running WHMCS (a billing system) and I want to be able to bring the pages into that, including things such as sliders and ther cool WordPressy things.

It is pretty straight forward, though it is a .tpl file I’d be using, but with no TPL info, all PHP (just the way it works).

Any help would be much appreciated.