Looks like you've gotten lots of advise/suggestions. Here's my 2 cents worth. I'd make 1 room the storage room. Line the walls with shelves. Put a 6' cutting table in the center. You can lay a big board ironing board on op of the cutting table for large ironing projects. Put UV block on the window, comes in a sheet.
The other room use for the act of quilting. Make it attractive, whatever that is to you, with plenty of ambiant light. Have plenty of task lights. Put UV block on the window. Put a small iron/cutting station next to you sewing center. Have plenty of design wall space. And drawers for your sewing tools, thread, notions. Ventilation: fan. Comfortable chair: an office chair that adjusts for height, tilt etc. If space a chair for company. I may think of more.