Drupal - Bootstrap for old PHP script

In a hurry and I have an old PHP application that pulls data from proprietary tables.  I have connected some of the data to a node, but now I need to display the data in a separate window when applicable.

So, using the old and large PHP script, just to get it functioning, I had to bootstrap Drupal.
Place this at the beginning of OldLarge.php


$drupal_dir = getenv("DOCUMENT_ROOT");
$current_directory = getcwd();
chdir($drupal_dir);


require_once './includes/bootstrap.inc';
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);

...
Do my Drupal stuff here....db_query() and whatever so that I can get results back from weird tables.
...

Then at the end of  OldLarge.php , add the final code....


chdir($current_directory);

Eventually...some day (which ends up being never) I will convert the OldLarge.php script to something more Drupalized.