When writing, please include a self-addressed stamped envelope with your letter of inquiry. Once you have exhausted all of the possibilities of finding more on your family at the local genealogical society, it is time to visit the local courthouse. Records of wills, estates and marriages may be found in the office of the local probate judge. The location of these types of records, including land transactions, varies by courthouse. Don't forget to visit the local library.
Most public libraries have genealogical information housed in their reference section.
It is quite possible that the library may have some books and family history holdings that the local genealogical society does not have in their archives. I am most familiar with the holdings of the downtown Spokane Public Library. Most of the holdings in this room are very delicate and relate to the history of the Northwest. Many of the items kept here are not to be photocopied and you may only take a pencil and paper into the room with you. There are many books of bibliographies, the very first phone books, histories of towns and their settlers.