You might want to think of more than quilting retreats. The place we go for retreats also rents out for family reunions and other groups. It will give you a larger pool of potential customers. Note that most adults won't share a bed with anyone other than their spouse, so a queen bed and a twin is for two unrelated adults or a couple and a child.
Think about how you will market the location. Direct mail to quilting groups? Attending quilt shows? What about a web site? Your location in a lightly populated area works against you I am afraid which is a good reason to broaden your customer base.