I also can only work on one quilt at a time. I have the plans and fabric for several quilts waiting for me to start them though. I can start on the next quilt if the first one is at the quilters. Now with knitting, I have about 10 projects cast on and in projects bags and I'm not bothered by them at all.
When I start a new quilt I have to clean my sewing room. I don't have to clean anything when working on a garment though. I just shove fabric out of the way and sew.
I also wind about 4-5 bobbins before I start a quilt.