Why not keep the 'old sewing room' as your sewing room and make the new room your 'new quilting room'. I don't know about you but when I'm "quilting" - I'm not "sewing" or "cutting fabrics".
Keep only the supplies you need for the longarm in the "quilting room" - buy duplicates if you need to...they're less than fabric per yard.
How about having someone make you a platform box the length of your longarm so you can stand on it. Say 36" deep by the length of your table.
Your friend can try a stool to sit on while longarming.