There is also the U.S. Classics Philatelic Society. They have a number of publications online that you can view or download for free. A few may serve to help.
http://www.uspcs.org/resource-cente...nic-library/There may not be a West Virginia Postal History Society, but from personal experience and sales on
ebay's, there is a demand for these covers. It may not be based on postmarks and stamps alone, but also pay attention to the sender and receiver. If there's letters inside that's a bonus. Some people have an interest in postal history beyond the philatelic realm and collect them for their genealogical interests and/or part of a town/country historical interests.