Mitch ... I see that MKC has already given you some links.
How did you make out with the boxes around your machine and extension table? Some have done similar using the rigid styrofoam insulation pieces, cut to size, covering them with a plastic tablecloth or clear plastic/vinyl that you buy by the yard.
Another possibility, if by chance you have an extension table that when pulled out, has somewhat of a shelf ... some have opened the table and set their machine on it. Then custom cut the filler board for the table to allow for the machine to set into it. Not sure if that makes sense? Or have taken a desk altering to allow a machine to set into it, and the desk surface to be your full table surface instead of your extension table.
Silicone spray on whatever surface you end up with, will help make things more slippery for your quilt to move a little easier as you work. Caution though .... overspray onto a hard floor surface can make it slip-sidey for humans, and the four legged ones who think they are human!!!