My sewing room is the old, circa 1954 kitchen and I love it. The only physical change I made was to take the doors off the front of all the cabinets, up and down. The drawers are a plus for patterns, etc. I guess I am strange but I left the double kitchen sink and I adore the tile counter tops and wrap around back splashes. The kitchen sink is an obvious plus but, oh my, those back splashes. Things hanging in front of my nose are much better than things I have to remember. A combination of Command strips and hangers with museum putty on those tiled wall parts does the trick: bobbin boards for 4 varieties of sewing machine, thread boards for cones and spools alike, nifty plastic bathroom-type hold everything things with suction cups for all the little stuff you can't do without and would "lose" otherwise. The list goes on.
Another thing about sewing in an old kitchen is there are more electrical outlets available. And then there are the lights. Besides the "great white eye" in the middle of the ceiling, there is the second white eye over the sink, and then the occasional lighting under the cabinets. The 19+ running feet of cabinet top is pretty good too. And the windows!
My sewing room is not beautiful but it does the job.
May all of us be as happy in our spaces as I am in mine!
Pat