Have a great time at your retreat!
Do you know if they are having projects for you, or if is a do your
own projects retreat?
I have a list somewhere of what I bring to retreats, will dig it out and post later, but #1 on the list is your machine and to be sure to have your FOOT PETAL and ALL attachments you want to be using over the weekend.
Almost anything else if you don't have it with you, someone else will...and will be willing to share.