Since I live between Vancouver and Whidbey Island, I'm wondering how one gets invited to one of these events?
If you go to the Vanrail website you can contact the Registrar, Rene Gourley, through that. We had spots up to the last minute. Actually a British rail fan and modeler found the site by accident while looking for local Vancouver places to railfan, contacted Rene out of curiosity, and that was how he got invtied!
Next Vanrail event will be Fall of 2017 but Soundrail in Seattle (and Whidbey) is next March and Northern rails in Edmonton is a year from now.
Hope that helps.