Welcome to our forum.
"Where does one find like-minded people in a local area -- or perhaps not more than two hundred miles away?"
All I can suggest is for you to look around on the following links:
Arkansas seems to be a sparse state in terms of an organized group that gets together. But you can also look for individuals on OKCupid. Try also doing a search for "Arkansas" on this site.
I've been to Seattle and greatly enjoyed my stay. I know they have a strong polyamorous presence there. I imagine they do in Vancouver, too.
Good luck in your search, and thanks for joining us.