Update May 2018: Kathryn gave an hour long workshop at the Canadian Positive Psychology Association biennial conference on May 24, 2018. Here are two resources for those who were not there. The description of writers' workshops starts on page 19 of the script.
Here are some resources that Kathryn is collecting for a book she is writing about experiments to build writing skill and confidence. At this point (January 2021), her list of experiments has grown to 32.