You are so fortunate to have been given these!! I love feedsacks and have small collection of them.
Muslin is always good with feedsacks. Here is a picture of a great feedsack quilt in your same pattern and an article you might find interesting.
http://www.quilthistory.com/feedsacks.htm
http://www.quilttownusa.com/Quilt_Ga...plaidholes.jpg