Well Wordesk is an UI where you can retrieve the result of a WebScript and display it.
Unfortunately you will need Java programming knowledge to do so.
A quick differentiation of Workdesk and WebScript solution is that Workdesk is accessing the
Alfresco Repository through CMIS and WebScripts are based on a native Alfresco API.
<blockquote>I would like to create Forms in Workdesk that update XML documents stored in Workdesk.</blockquote>
Alfresco Workdesk is an UI which can be configured (XML files which are contained in Workdesk represents the configuration), WebScripts is a feature of Alfresco Repository to provide extensibility (UI representation, Service Access).
<blockquote>
I would also like to create screens to 'Show Records' based on Alfresco-stored XML documents, but only portions of the XML data, not the docs themselves. Saving changes on the Form in Workdesk should use Alfresco's Revisions system to store the changes to the XML documents.
</blockquote>
As I understand Workdesk already provide such feature, it is named "virtual structures" (maybe I misunderstood your requirement). But they are not saved/contained in the Alfresco repository, if you look into the Workdesk deplyoment under <em>/WEB-INF/opencmis</em> you will see folders with names like "owsearchtempaltes", "owpreferences" and "others" where XML files are contained.
To answer your question, WebScripts are not part of Alfresco Workdesk, even though you still
can access them from Workdesk.