Suzanne Johnson is posting Jackson Square on her website Preternatura. There is a tab at the top labelled Jackson Square funnily enough where you can access the story.
The story will only be online for one week before it is removed so you will need to get in fast. Johnson is hoping to have the e-book version out in July.
FYI River Road is now out in paperback which is awesome as my copy of Royal Street was looking lonely.