Good luck on your boxing up and on your move.
I just recently did this and came out with over 100 boxes from my sewing room.
Then health issues and other factors entered into the picture so I changed my mind.
Now, as I unpack the boxes, I am really going through everything and have already filled a big box of items to "go away". It helps that 2 of my girlfriends are coming for the Houston Quilt Festival and can "shop" the box before we go to the show. I already have someplace to donate the fabric that they do not take. I am going to try moving again in about a year and hope to have reduced my stash and other projects by then so I have fewer boxes.
One thing for sure, I have bought a lot less fabric and other sewing items since I boxed everything up and saw just how much I had!