We have the same question. The escalation email is not very useful if we cannot provide a link to the overdue task. We would also like to include the name of the user task and the date that the task was assigned. But the Context Browser in SharePoint Designer doesn't give us access to the workflow activity information. Anyone come up with a solution?

In the meantime, we are including a hyperlink to direct the users to a page that includes the K2 worklist filtered for the specific worklow. So at least the users can see all of their open tasks for the workflow. However, it would be simpler to provide a direct link to the overdue task in the escalation email.