Well, to do it in JS you'd just ... do it in JS
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I could easily see a page with two drop-down menus ("select elements") to let you pick the to/from zones, and a button. See
https://wiki.project1999.com/Per-Level_Hunting_Guide for a general idea of wiki pages with custom forms.
When someone clicks the button, some code would grab the two zone names, plug it into the algorithm, and then that algorithm would return an array of zones. The code would then add a bunch of properly-ordered links to the zones on the page, describing the path from A to B.
If you can get the algorithm part working I'd be happy to help with the form, connecting it to the algorithm, and the display of the results ... I'm just not willing to sign up to write the algorithm itself.
As for using an extension, I'm not a PHP dev, but you can see how the existing custom extensions (for stuff like the auction tracker or the dynamic zone lists work) by downloading the source code here:
https://wiki.project1999.com/utils/wikiUtils.php ("Custom Extensions Source").