You can ask at local quilt shops. Often word of mouth, too.
Retreats can be just a group of friends, or folks from all over. Different teachers, and such. Often you share a room with someone, food(most) is included as part of the cost. All have a great time! Sometime there are themes also. Hope you find one you'd like to go to.
An idea: call Jean Wells' quilt shop in Sisters, OR. They may have some ideas for you~