Some groups have CAMPS instead of retreats, so also google Quilt Camp instead of just Quilt retreat. Do you have any conference/retreat centers/summer camps near you? Ask them if they host any quilt groups throughout the year. In some cases, the location will sponsor the quilt event and will be able to provide you with information about the next event. In other cases an outside group will just be renting their facilities, but the place may be able to provide you with a name/contact/website for more info.