Do you have a spare bed that you can spread it out on to leave until the next guest arrives? Don't let it be used as a quilt in case it is less intact than it looks. Hand appliqueing patches to the worn out patches is not that hard to do. If those occasional patches is all that has worn out on the quilt, practicing your applique technique will be easy if it is spread out on a bed to ease the weight of the quilt. Getting replacement fabric is as easy as getting an old feedsack print that you like or even a solid color print (matching the tone of one of the colors in the quilt -- nothing brighter!) to make it easier for future generations to see where their relative repaired the quilt.
Your great great grandmother is very happy that you have intentions for this wonderfully made double wedding ring quilt!