I am embarrassed to admit that I didn't read your post well, and I responded as if you were washing a new quilt.

For an older (not antique) quilt, I would take it to a laundromat and wash it in the biggest front-loading machine available. I then tumble it dry (at the laundromat) for a little while, until I can drape it over a couple clotheslines without much water weight.

I wash mine in Woolite with cold water and dry on low heat. They come out really pretty and soft.